The reason "loved ones" is normally plural is because the people in question are unknown in form or quantity. "Loved ones" is a generic way of referring to any and all people of significant importance to an individual or group.
The New York Times: Remembering ESPN’s Chris Mortensen, who changed how the NFL is covered
LOVED definition: held in deep affection; cherished. See examples of loved used in a sentence.
LOVED definition: 1. past simple and past participle of love 2. to like another adult very much and be romantically…. Learn more.
Define loved. loved synonyms, loved pronunciation, loved translation, English dictionary definition of loved. n. 1. A strong feeling of affection and concern toward another person, as that arising from kinship or close friendship. 2. A strong feeling of affection...
love (luv), n., v., loved, lov ing. n. a profoundly tender, passionate affection for another person. a feeling of warm personal attachment or deep affection, as for a parent, child, or friend. sexual passion or desire. a person toward whom love is felt; beloved person; sweetheart. (used in direct address as a term of endearment, affection, or the like): Would you like to see a movie, love? a ...
What is the etymology of the word loved? loved is formed within English, by derivation. Etymons: love v.1, ‑ed suffix1.
loved, adj. & n. meanings, etymology and more | Oxford English Dictionary
From Middle English loved, luvd, from Old English lufode, first and third person singular past indicative of lufian; and Middle English loved, iloved, from Old English ġelufod, past participle of lufian; both equivalent to love + -ed.