Translation guide
In Japanese, expressing 'set of three' depends on what the three items are and how they are grouped. Common counters, specific words for triplets or trios, and general terms for three-piece sets are covered here.
To refer to a set or group of three items, using the generic counter for sets.
This set of three plates is my favorite.
Literally 'three-item set'. Often used in commercial contexts for products sold as a set of three.
This set of three is a bargain.
To refer to a group of three people or things that form a unit, like a trio or triplet.
A group of three people, a trio. Commonly used for a band, team, or any group of three individuals.
They are a trio band.
Triplets (three children born at the same time). Specifically for siblings.
Loanword from English 'trio'. Often used for musical groups or a set of three people.
To describe a set of three items that are identical or part of a collection, like a three-piece set.
To refer to a set of three items that are worn or used together, like a three-piece suit or tool set.
To express a set of three things that are part of a series, like a trilogy or three-volume set.
Japanese uses specific counters for different types of objects. For a set of three, you can often use the number + counter + セット (setto) or 組 (gumi). The counter depends on the item: 個 (ko) for small objects, 枚 (mai) for flat objects, 本 (hon) for long objects, etc. For example, 'a set of three plates' can be 三枚セット (sanmai setto).
Directly translating 'set of three' as 三つのセット (mittsu no setto) is understandable but not natural. Use the appropriate counter or specific term instead.
彼女は三つ子の母親です。
She is a mother of triplets.
I listened to a jazz trio performance.
I bought a set of three chairs.
This three-piece tool set is handy.