Newlyweds are a couple who married only recently. The happy newlyweds, a card for the newlyweds, newlyweds' first home.
It is almost always plural, since it names the pair rather than either one. There is no fixed period after which the word stops applying, but it is generally the first year. It is written as one word.
1nounnewlywedsA couple who married only recently.
“The newlyweds left for their honeymoon the morning after the wedding.”
newlyweds is a couple.
newlywed comes from newly + wed.
Etymology from Wiktionary, CC BY-SA