English lifted its word from Old French in the 13th century — itself possibly Frankish, carrying some early sense of motion or pull. Spanish declined that inheritance entirely and reached back through Latin 'ballare,' a word some trace to a Greek verb for throwing, giving the same act a different physical imagination. Chinese built 舞 from the image of a dancer's spread sleeves; the modern character still shows two feet stepping in opposite directions at the base. Esperanto crystallized the European consensus into a transparent morpheme and let it go.
Entered Middle English in the 13th century from Old French 'dancier' (also 'danser'). The Old French word's ultimate origin is disputed — Frankish *dansōn (to drag, pull) is the most commonly cited source, but Old Low Franconian and even a Latin derivation have been proposed. No secure PIE root exists.
Noun form; the verb is 'bailar.' Descends from Late Latin 'ballare' (to dance), itself possibly from Late Greek 'ballizein' (to dance, jump about), though this Greek connection is not universally accepted. Entirely separate provenance from English 'dance' and Old French 'dancier.'
In oracle-bone script (c. 1200 BCE), 舞 shows a human figure with both arms spread wide, holding tassels or feathered ornaments — a ceremonial dancer mid-gesture. The modern character preserves this in the upper component 無 (the dancer with sleeves aloft) and grounds it with 舛 below: two feet angled against each other, the geometry of a step inscribed directly into the glyph.
The semantic relationship between 舞 (dance) and 無 (nothing/without) is an accident of phonetic borrowing in later script evolution; the two characters share an ancient form but diverged in meaning. Paleographic analysis of oracle-bone forms is ongoing and some details remain debated.
Verb infinitive. Noun form: 'danco.' Dancer: 'dancisto' (danc- + -ist- [practitioner] + -o [noun ending]). Zamenhof drew the root from the common Romance-Germanic dance vocabulary (French 'danser,' German 'tanzen,' Italian 'danzare,' etc.), assembling the form he likely considered most internationally recognizable.
Dancing preceded language; each of these words is language's belated attempt to claim something the body already owned.