Real Dictionary

segment
countable noun: A segment of a circle is one of the two parts into which it is divided when you draw a straight line through it.
countable noun: A segment of a market is one part of it, considered separately from the rest.
countable noun: A segment of fruit such as an orange or grapefruit is one of the sections into which it is easily divided.
countable noun: A segment of something is one part of it, considered separately from the rest.
verb: If a company segments a market, it divides it into separate parts, usually in order to improve marketing opportunities.

segment in American English
any of the parts into which a body is separated or separable; division; section
to divide into segments
to separate or divide into segments
noun: one of the parts into which something naturally separates or is divided; a division, portion, or section

segment in British English
noun: a part of a line or curve between two points
verb: to cut or divide (a whole object) into segments