1.
tie; draw; even
A result where neither side wins, particularly in games like rock-paper-scissors. Can also be used figuratively to mean being even or quits.
あいこでしょ！
It's a tie! (Let's go again!)
Most commonly heard in the context of じゃんけん (rock-paper-scissors). When both players choose the same hand, the result is あいこ, and players chant あいこでしょ！ before throwing again.
Common collocations
Usage
Beyond games, あいこ can mean "we're even" or "quits" in everyday situations — for example, after exchanging favors. The word can also be written as 相子, though the hiragana form is more common.