
Breakfast [late Middle English]: break + fast
Break [Old English]: The Old English form of break was
brecan, which has a Germanic source and is related to Dutch
breken and German
brechen. It has an Indo-European root shared by Latin
frangere 'to break', which gave English words such as
fracture.
Fast [Old English]: Old English
faestan 'abstain from or go without food' has a Germanic origin; it is related to Dutch
vasten and German
fasten, as well as to Old Norse
fasta, the source of the noun.