Word derivation is the creation of a word from another word, according to Oxford Dictionary. An example of word derivation is the adjective "drinkable" being derived from the verb "drink." Derivation can also be from other languages, such as the English "amour," which is derived from the Old French "amour."
The Online Etymology Dictionary reports that amour is ultimately derived from the Latin, "amorem," which translates to "Love, affection and a strong friendly feeling." It could be used by sons or brothers, but especially pertains to sexual love. This is derived ultimately from Latin and Celtic root words like "am-."