noun
one vote; one ballot
Refers to a single vote or ballot in an election or decision-making process. Often used in contexts like 一票を投じる (cast a vote) or 一票の差 (a margin of one vote).
選挙で彼に一票を投じた。
I cast a vote for him in the election.
その法案は一票の差で可決された。
The bill was passed by a margin of one vote.
投票 is the general act of voting or a vote as a concept, while 一票 specifically means one individual vote or ballot.
Compound of 一 (one) and 票 (vote, ballot). The reading いっぴょう follows standard rendaku voicing of ひょう.