verb

• (transitive) To pull or gather up (an item of fabric).
• (transitive) To push into a snug position; to place somewhere safe, or handy, or somewhat hidden.
  "Tuck in your shirt.  I tucked in the sheet.  He tucked the $10 bill into his shirt pocket."
• (intransitive, often with "in" or "into") To eat; to consume.
• (ergative) To fit neatly.
  "The sofa tucks nicely into that corner.  Kenwood House is tucked into a corner of Hampstead Heath."

noun

• (sewing) A fold in fabric that has been stitched in place from end to end, as to reduce the overall dimension of the fabric piece.
• (medicine, surgery) A plastic surgery technique to remove excess skin.
  "tummy tuck"
• (music, piano, when playing scales on piano keys) The act of keeping the thumb in position while moving the rest of the hand over it to continue playing keys that are outside the thumb.
• (diving, gymnastics) A curled position, with the shins held towards the body.

noun

• (archaic) A rapier, a sword.
  "[…] with force he labour'd / To free's blade from retentive scabbard; / And after many a painful pluck, / From rusty durance he bail'd tuck […]"