Tucked means that something or someone is placed snugly and securely inside or into something else.
When we say that something is tucked in, it usually means that it's being put away carefully. For example, if you're putting a blanket on your bed at night, you would tuck the corners under the mattress so it stays in place. You might also hear someone talk about their shirt being tucked into their pants, which means the shirt is pulled up and into the waistband of the pants for a neat look. Sometimes people will even tuck their hair away when they're trying to keep it out of their face while they work or exercise.
How common is "tucked"?
Word tucked is considered rare in modern English. It appears most frequently in fiction texts and less often in other writings.
Definitions
verb
To pull or gather up (an item of fabric).
To push into a snug position; to place somewhere safe or somewhat hidden.
Example: Tuck in your shirt. I tucked in the sheet. He tucked the $10 bill into his shirt pocket.
(often with "in" or "into") To eat; to consume.
To fit neatly.
Example: The sofa tucks nicely into that corner. Kenwood House is tucked into a corner of Hampstead Heath.
To curl into a ball; to fold up and hold one's legs.
Example: The diver tucked, flipped, and opened up at the last moment.
To sew folds; to make a tuck or tucks in.
Example: to tuck a dress
To full, as cloth.
(of a drag queen, trans woman, etc.) To conceal one’s penis and testicles, as with a gaff or by fastening them down with adhesive tape.
Example: Honey, have you tucked today? We don’t wanna see anything nasty down there.
(when playing scales on piano keys) To keep the thumb in position while moving the rest of the hand over it to continue playing keys that are outside the thumb.