sin·glet
noun/ˈsɪŋɡlət/
/ˈsɪŋɡlət/
(British English)- a piece of clothing without arms, worn under or instead of a shirt; a similar piece of clothing worn by runners, etc.
背心；无袖汗衫；运动背心 Word Originmid 18th cent. (originally denoting a man's short jacket): from single (because the garment was unlined) + -et, on the pattern of doublet.