Since it is thrown around so much.
Let's define what the test statistic is

A test statistic is a random variable that is calculated from sample data and used in a hypothesis test. You can use test statistics to determine whether to reject the null hypothesis. The test statistic compares your data with what is expected under the null hypothesis. The test statistic is used to calculate the pvalue.
A test statistic measures the degree of agreement between a sample of data and the null hypothesis. Its observed value changes randomly from one random sample to a different sample. A test statistic contains information about the data that is relevant for deciding whether to reject the null hypothesis. The sampling distribution of the test statistic under the null hypothesis is called the null distribution. When the data show strong evidence against the assumptions in the null hypothesis, the magnitude of the test statistic becomes too large or too small depending on the alternative hypothesis. This causes the test's pvalue to become small enough to reject the null hypothesis.

A test statistic is a random variable that is calculated from sample data and used in a hypothesis test. You can use test statistics to determine whether to reject the null hypothesis. The test statistic compares your data with what is expected under the null hypothesis. The test statistic is used to calculate the pvalue.
A test statistic measures the degree of agreement between a sample of data and the null hypothesis. Its observed value changes randomly from one random sample to a different sample. A test statistic contains information about the data that is relevant for deciding whether to reject the null hypothesis. The sampling distribution of the test statistic under the null hypothesis is called the null distribution. When the data show strong evidence against the assumptions in the null hypothesis, the magnitude of the test statistic becomes too large or too small depending on the alternative hypothesis. This causes the test's pvalue to become small enough to reject the null hypothesis.
https://support.minitab.com/enus/minitabexpress/1/helpandhowto/basicstatistics/inference/supportingtopics/basics/whatisateststatistic/Ok but what is the test statistic. The definition is not clear. When I look at my output, which number is the test statistic? The Z value? The p value? The coefficient (lol)? The standard error?
What exactly IS it 
A test statistic is a random variable that is calculated from sample data and used in a hypothesis test. You can use test statistics to determine whether to reject the null hypothesis. The test statistic compares your data with what is expected under the null hypothesis. The test statistic is used to calculate the pvalue.
A test statistic measures the degree of agreement between a sample of data and the null hypothesis. Its observed value changes randomly from one random sample to a different sample. A test statistic contains information about the data that is relevant for deciding whether to reject the null hypothesis. The sampling distribution of the test statistic under the null hypothesis is called the null distribution. When the data show strong evidence against the assumptions in the null hypothesis, the magnitude of the test statistic becomes too large or too small depending on the alternative hypothesis. This causes the test's pvalue to become small enough to reject the null hypothesis.
https://support.minitab.com/enus/minitabexpress/1/helpandhowto/basicstatistics/inference/supportingtopics/basics/whatisateststatistic/Ok but what is the test statistic. The definition is not clear. When I look at my output, which number is the test statistic? The Z value? The p value? The coefficient (lol)? The standard error?
What exactly IS itThe test statistic is the quantity used to verify the hypothesis test.

A test statistic is a random variable that is calculated from sample data and used in a hypothesis test. You can use test statistics to determine whether to reject the null hypothesis. The test statistic compares your data with what is expected under the null hypothesis. The test statistic is used to calculate the pvalue.
A test statistic measures the degree of agreement between a sample of data and the null hypothesis. Its observed value changes randomly from one random sample to a different sample. A test statistic contains information about the data that is relevant for deciding whether to reject the null hypothesis. The sampling distribution of the test statistic under the null hypothesis is called the null distribution. When the data show strong evidence against the assumptions in the null hypothesis, the magnitude of the test statistic becomes too large or too small depending on the alternative hypothesis. This causes the test's pvalue to become small enough to reject the null hypothesis.
https://support.minitab.com/enus/minitabexpress/1/helpandhowto/basicstatistics/inference/supportingtopics/basics/whatisateststatistic/
Ok but what is the test statistic. The definition is not clear. When I look at my output, which number is the test statistic? The Z value? The p value? The coefficient (lol)? The standard error?
What exactly IS itThe test statistic is the quantity used to verify the hypothesis test.
The p value. Got it.

A test statistic is a random variable that is calculated from sample data and used in a hypothesis test. You can use test statistics to determine whether to reject the null hypothesis. The test statistic compares your data with what is expected under the null hypothesis. The test statistic is used to calculate the pvalue.
A test statistic measures the degree of agreement between a sample of data and the null hypothesis. Its observed value changes randomly from one random sample to a different sample. A test statistic contains information about the data that is relevant for deciding whether to reject the null hypothesis. The sampling distribution of the test statistic under the null hypothesis is called the null distribution. When the data show strong evidence against the assumptions in the null hypothesis, the magnitude of the test statistic becomes too large or too small depending on the alternative hypothesis. This causes the test's pvalue to become small enough to reject the null hypothesis.
https://support.minitab.com/enus/minitabexpress/1/helpandhowto/basicstatistics/inference/supportingtopics/basics/whatisateststatistic/
Ok but what is the test statistic. The definition is not clear. When I look at my output, which number is the test statistic? The Z value? The p value? The coefficient (lol)? The standard error?
What exactly IS it
The test statistic is the quantity used to verify the hypothesis test.The p value. Got it.
No. The pvalue is a function of the test statistic. It maps the test statistic to an integral of the hypothesis density.

A test statistic is a random variable that is calculated from sample data and used in a hypothesis test. You can use test statistics to determine whether to reject the null hypothesis. The test statistic compares your data with what is expected under the null hypothesis. The test statistic is used to calculate the pvalue.
A test statistic measures the degree of agreement between a sample of data and the null hypothesis. Its observed value changes randomly from one random sample to a different sample. A test statistic contains information about the data that is relevant for deciding whether to reject the null hypothesis. The sampling distribution of the test statistic under the null hypothesis is called the null distribution. When the data show strong evidence against the assumptions in the null hypothesis, the magnitude of the test statistic becomes too large or too small depending on the alternative hypothesis. This causes the test's pvalue to become small enough to reject the null hypothesis.
https://support.minitab.com/enus/minitabexpress/1/helpandhowto/basicstatistics/inference/supportingtopics/basics/whatisateststatistic/
Ok but what is the test statistic. The definition is not clear. When I look at my output, which number is the test statistic? The Z value? The p value? The coefficient (lol)? The standard error?
What exactly IS it
The test statistic is the quantity used to verify the hypothesis test.
The p value. Got it.No. The pvalue is a function of the test statistic. It maps the test statistic to an integral of the hypothesis density.
Speak English. If it is not the p value, which I can easily see in my output, then what number of my output is it?

A test statistic is a random variable that is calculated from sample data and used in a hypothesis test. You can use test statistics to determine whether to reject the null hypothesis. The test statistic compares your data with what is expected under the null hypothesis. The test statistic is used to calculate the pvalue.
A test statistic measures the degree of agreement between a sample of data and the null hypothesis. Its observed value changes randomly from one random sample to a different sample. A test statistic contains information about the data that is relevant for deciding whether to reject the null hypothesis. The sampling distribution of the test statistic under the null hypothesis is called the null distribution. When the data show strong evidence against the assumptions in the null hypothesis, the magnitude of the test statistic becomes too large or too small depending on the alternative hypothesis. This causes the test's pvalue to become small enough to reject the null hypothesis.
https://support.minitab.com/enus/minitabexpress/1/helpandhowto/basicstatistics/inference/supportingtopics/basics/whatisateststatistic/
Ok but what is the test statistic. The definition is not clear. When I look at my output, which number is the test statistic? The Z value? The p value? The coefficient (lol)? The standard error?
What exactly IS it
The test statistic is the quantity used to verify the hypothesis test.
The p value. Got it.
No. The pvalue is a function of the test statistic. It maps the test statistic to an integral of the hypothesis density.Speak English. If it is not the p value, which I can easily see in my output, then what number of my output is it?
Just count the stars.

A test statistic is a random variable that is calculated from sample data and used in a hypothesis test. You can use test statistics to determine whether to reject the null hypothesis. The test statistic compares your data with what is expected under the null hypothesis. The test statistic is used to calculate the pvalue.
A test statistic measures the degree of agreement between a sample of data and the null hypothesis. Its observed value changes randomly from one random sample to a different sample. A test statistic contains information about the data that is relevant for deciding whether to reject the null hypothesis. The sampling distribution of the test statistic under the null hypothesis is called the null distribution. When the data show strong evidence against the assumptions in the null hypothesis, the magnitude of the test statistic becomes too large or too small depending on the alternative hypothesis. This causes the test's pvalue to become small enough to reject the null hypothesis.
https://support.minitab.com/enus/minitabexpress/1/helpandhowto/basicstatistics/inference/supportingtopics/basics/whatisateststatistic/
Ok but what is the test statistic. The definition is not clear. When I look at my output, which number is the test statistic? The Z value? The p value? The coefficient (lol)? The standard error?
What exactly IS it
The test statistic is the quantity used to verify the hypothesis test.
The p value. Got it.
No. The pvalue is a function of the test statistic. It maps the test statistic to an integral of the hypothesis density.Speak English. If it is not the p value, which I can easily see in my output, then what number of my output is it?
It depends on your research question. You may not find that quantity in the typical regression output.