An interesting etymology for these two related words. In English, the word meat translates to carne in Italian.
Etymology: < Italian carnevale, carnovale (whence French carnaval), evidently related to the medieval Latin (11–12th cent.) names carnelevārium, carnilevāria, carnilevāmen, cited by Carpentier in additions to Du Cange. These appear to originate in a Latin *carnem levāre, or Italian *carne levare (with infinitive used subst. as in il levar del sole sunrise), meaning ‘the putting away or removal of flesh (as food)’, the name being originally proper to the eve of Ash Wednesday. The actual Italian carnevale appears to have come through the intermediate carnelevale, cited by Carpentier from a document of 1130.
The history of the word is illustrated by the parallel medieval Latin name carnem laxare (cited by Carpentier from a charter of 1050), corresponding to Italian *carne lasciare ‘leaving or forsaking flesh’, whence, apparently by contraction, the modern carnasciale = carnevale. Carnem laxare, *carne lasciare, *carnelasciale, carnasciale, form a series exactly parallel to *carnem levare, *carne levare, carnelevale, carnevale. Other names having a similar reference are, for Shrove Tuesday, carnicapium ‘flesh-taking’, and carnivora [dies]; for Lent or its beginning, carniprivium, carnisprivium, privicarnium, < privare to deprive. In all these, ‘flesh’ means meat, and that it was understood to mean the same in carnelevare is shown by many early quotations in Du Cange; e.g. in a MS. of beg. of 13th cent. ‘De ludo Carnelevar. In Dominica dimissionis carnis,’ etc. Also ‘Dominica ad vel ante carnes tollendas’; with which compare the Spanish carnes tolendas, ‘shrove-tide’. We must therefore entirely reject the suggestion founded on another sense of levare, ‘to relieve, ease’, that carnelevarium meant ‘the solace of the flesh (i.e. body)’ before the austerities of Lent. The explanations ‘farewell flesh, farewell to flesh’ (from Latin vale) found already in Florio, and ‘down with flesh!’ (from French aval), belong to the domain of popular etymology. (Compare Dr. Chance in Notes & Queries s. 7 IV. 82.)
Etymology: < French Mardi gras last day of Carnival (see also note s.v. CARNIVAL n. 1; earliest attested in 1552 as name of a personified character in Rabelais) < Mardi Tuesday (see TUESDAY n. and adv.) + gras fatty, greasy, (of a day) on which the consumption of meat products is permitted (see GREASE n.).(Show Less)
Shrove Tuesday, esp. as celebrated in some traditionally Roman Catholic areas or regions with a carnival; the last day of the Carnival or pre-Lenten season. Also (in extended use): a carnival held at any time. Frequently attrib.