The phrase "first segment" refers to the initial part or section of something, usually indicating the beginning of a series or sequence. Full definition
Insulin is a hormone produced in the pancreas, which is located in the abdomen near the stomach and first segment of the small intestine. (hospital4cats.com)
First segment consists the information about the candidate where the details to be included are name along with the contact number and address. (template.net)
The $ 19.9 million first segment on the bypass is funded with $ 10 million from the American Recovery and Reinvestment Act (ARRA) Transportation Investment Generating Economic Recovery (TIGER) grant program. (transportation.gov)