How does 衣衫 compare to 衣服 in terms of meaning and flavour? I am reading a short story (set around 1976) by 魏微 (born in 1970 in Jiangsu, studied in Nanjing). The word 衣衫 repeatedly occurs. I searched the net and found references from 紅樓夢 and 唐詩, but the short story is among the easiest I have ever read, making but sparse use of 成語 and fancy vocabulary.

My dictionary defines 衣衫 as clothes. Is there a difference to 衣服？ Any regional flavour, literary flavour or era related flavour for which one may choose it?

I searched jukuu and it seems to be rare outside fixed expressions. 魏微 uses it quite casually:


  ⋯我母亲那时很喜欢我，为我做很多漂亮的衣衫⋯


Or:


  我穿着最好看的衣衫，倚在家门口的一棵老槐树上,⋯
In olden time, there might be difference between the two terms

「衣 」[ (2) [upper garment;jacket]
衣,所以蔽体者也。上曰衣,下曰裳。]

and 

「衫」, [(1) 古代指无袖头的开衩上衣 [sleeveless jacket with vent in the sides of a jacket]. ]

In modern Chinese language, both 衣 and 衫 simply refers to 'clothes one wears on his upper body'

Together, 「衣衫 」is a compound word for the general term 'upper garment' much like 「刀劍 」(knife and sword) is a general term for 'weapons'

「服」as a noun, refers 'every article of clothing one wear on his person'. For example:  「軍服」(military uniform), 「制服」(uniform). 

「服」is also a verb for 'to wear' 

Together,「衣服」is a general term for 'clothes/clothing' just like 「刀斧」(knife and axe) is a general term for 'weapons'


  「衣服」 is much more common than 「衣衫」 in day-to-day words.


A related term is 「衣裳」(upper garment + lower garment), which is also a general term for 'clothing'