A borrowing or loanword is when a word from language A is added to the lexicon of language B, with whatever phonological adaptations are necessary.
But is a cognate only a word directly inherited from an ancestor language, or is it correct to say that any two words than can be traced back to a common ancestor word are cognates?
Obviously in the history of a word both things can happen:
- An Old English word and its descendant in Modern English are cognates.
- Is a word borrowed into Old English and its descendant in Modern English cognates?
- Would the Modern English word be cognate to the original word in the language that lent it to Old English?
- Would the Modern English word be cognate to a modern word in another modern language descended from the word in its ancestor language that Old English borrowed it from?
How should we most correctly use the term cognate?