breast-stroke (n.)

Old English breost "mammary gland of a woman, bosom; the thorax or chest, part of the body between the neck and the belly; mind, thought, disposition," from Proto-Germanic *brust-/*breust- "breast" (source also of Old Saxon briost, Old Frisian briast, Old Norse brjost, Dutch borst, German brust, Gothic brusts), perhaps literally "swelling" and from PIE root *bhreus- "to swell, sprout" (source also of Middle Irish bruasach "having a broad, strong chest," Old Irish bruinne "breast").

The spelling conforms to the Scottish and northern England dialectal pronunciation. The figurative sense of "seat of the emotions and affections, repository of designs and secrets" was in Old English. Breast-plate "armor for the front of the body" is from late 14c. Breast-pump is from 1821.

"act of striking," c. 1300, probably from Old English *strac "stroke," from Proto-Germanic *straik- (source also of Middle Low German strek, German streich, Gothic striks "stroke"); see stroke (v.).

The meaning "mark of a pen" is from 1560s; that of "a striking of a clock" is from mid-15c. Sense of "feat, achievement" (as in stroke of luck, 1853) first found 1670s; the meaning "single pull of an oar or single movement of machinery" is from 1731. Meaning "apoplectic seizure" is from 1590s (originally the Stroke of God's Hand). Swimming sense is from 1800.