While I see 衣類 and 衣服 as more general concepts in comparison to 服, I am very unsure of the difference between them.
What situations explicitly call for one over the other? In what situations are both or all three acceptable?
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Sign up to join this communityShogakukan's J-J Ruigo Reikai Thesaurus Dictionary has this to say about usage differences for 衣服 and 衣類.
Just plain old 服 isn't included in the same thesaurus entry, appearing instead under the entry for 洋服 ("western clothes"). Notably, 服 here in the thesaurus is glossed as "a dress" rather than "clothes", and the brief Japanese definition given in the thesaurus as common to both 洋服 and 服 states:
The JA-JA dictionary I have says:
As a further data point, the usage examples in Shogakukan's Progressive Japanese-English Dictionary entry for 服 almost all suggest that 服 may imply more of a set outfit. Here are a few excerpted examples (emphasis mine):
服装 meanwhile has its own thesaurus entry, but the section about usage discusses only 装い in detail. The English gloss for 服装 is given as "dress; costume", while the brief Japanese definition states:
服装
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