do

From Middle English don, from Old English dōn, from Proto-West Germanic *dōn, from Proto-Germanic *dōną, from Proto-Indo-European *dʰeh₁- (“to put, place, do, make”).

For senses 4 and 5, compare Old Norse duga, also Northern English dow.

The past tense form is from Middle English didde, dude, from Old English dyde, *diede, an unexpected development from Proto-Germanic *dedǭ/*dedē (the expected reflex would be *ded), from Proto-Indo-European *dʰédʰeh₁ti, an athematic e-reduplicated verb of the same root *dʰeh₁-.

The meaningless use of do in interrogative, negative, and affirmative sentences (e.g. "Do you like painting?" "Yes, I do"), existing in some form in most Germanic languages, is thought by some linguists to be one of the Brittonicisms in English, calqued from Brythonic. It is first recorded in Middle English, where it may have marked the perfective aspect, though in some cases the meaning seems to be imperfective. In Early Modern English, any meaning in such contexts was lost, making it a dummy auxiliary, and soon thereafter its use became mandatory in most questions and negations.

Doublets include deed, deem, and -dom, but not deal.

Other cognates include, via Latin, English feast, festival, fair (“celebration”), via Greek, English theo-, theme, thesis, and Sanskrit दधाति (dadhāti, “to put”), धातृ (dhātṛ, “creator”) and धातु (dhātu, “layer, element, root”).

Coined by Italian musicologist Giovanni Battista Doni in 1635 as an easier-to-sing open-syllable revision to the solmization ut of Guido of Arezzo, from the first syllable of Latin Dominus (“The Lord”) (speculated by some to be an ulterior abbreviation of Giovanni Battista Doni) on the pattern of other Latinate solfège with the stated justification that God is the tonic and root of the world.

Shortening of dozen.