Old English breost "breast, bosom; mind, thought, disposition," from Proto-Germanic *breustam "breast" (cf. 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" (cf. Middle Irish bruasach "having a broad, strong chest," Old Irish bruinne "breast"). The spelling conforms to the Scottish and northern England dialectal pronunciation. Figurative sense of "seat of the emotions" was in Old English.
breast (brěst)
n.
Either of two milk-secreting, glandular organs on the chest of a woman; mammary gland; mamma.
A corresponding rudimentary gland in the male.
The superior ventral surface of the human body, extending from the neck to the abdomen.