The phrase "first half" can be replaced with several synonyms depending on the context in which it is used. In the context of a game, "opening half" or "initial half" can be used interchangeably. In the context of a year, "first six months" or "early year" can be used to replace "first half". Similarly, in the context of a semester at school, "semester one" or "beginning semester" are synonyms that can replace "first half". Other synonyms for "first half" include "initial period," "preliminary phase," "commencement period" and "onset period." The use of any of these synonyms can add variety to our language and make our writing more impactful.