BALL-ERO

Maurice Ravel's famous orchestral piece Bolero (one of my favorite compositions) is named after a genre of Spanish dance, particularly played in 3/4 time. The word for that has been in use since the 1780s, and unsurprisingly comes from Spanish. This comes from the earlier word bola, meaning "ball"; it's thought that the connection was a  shared whirling motion. Bola traces to the Latin word bulla, which was used in reference to round things like a "bubble" or "knob". Possibly through Gaulish, that ultimately derives from the Proto-Indo-European root bhel, meaning "to swell". If you were wondering, bhel is also the source of the English word ball, as well as a myriad of other swelling-related words, such as balloon, boulder, bull, and bowl. Today, bolero makes up just under 0.00001% of all words used in the English language.