join in

WordReference Random House Learner's Dictionary of American English © 2026

join /dʒɔɪn/   v. 

1. to (cause to) come into or be in contact or connection with;
   connect: [~ + object]
   They all joined hands.
   [no object]
   Their hands joined and they formed a circle.
   [~ + up + object]
   joined up the hose with the faucet.
   [~ + object + up]
   joined the parts up into a whole.
2. to come into contact or union with: [~ + object]
   The brook joins the river.
   [no object]
   The two rivers joined before they reached the sea.
3. to (cause to) come together in a particular relation or for a specific purpose;
   unite: [~ + object]
   Join us and help fight poverty.
   [~ + with + object]
   Join with us in our campaign.
4. to become a member of:
   [~ + object] to join a club.
5. to enlist (in), as a branch of the armed forces: [~ + object]
   to join the Navy.
   [~ + up]
   joined up and went to sea.
6. to come into the company of;
   meet or accompany (someone), so as to participate with or in some activity:
   [~ + object] Can you join us for a drink?
7. to bring into close relationship:
   [~ + object] joined them in matrimony.
8. join in, to take part in;
   become involved in: [no object]
   was too shy to join in.
   [~ + in + object]
   Wouldn't you like to join in the fun?

See -junc-.

WordReference Random House Unabridged Dictionary of American English © 2026

join  ( join), v.t. 

1. to bring in contact, connect, or bring or put together:
   to join hands; to join pages with a staple.
2. to come into contact or union with:
   The brook joins the river.
3. to bring together in a particular relation or for a specific purpose, action, etc.;
   unite:
   to join forces against the smugglers.
4. to become a member of (an organization, party, etc.):
   to join a club.
5. to enlist in (one of the armed forces):
   to join the Navy.
6. to come into the company of;
   meet or accompany:
   I'll join you later.
7. to participate with (someone) in some act or activity:
   My wife joins me in thanking you for the gift.
8. to unite in marriage.
9. to meet or engage in (battle, conflict, etc.):
   The opposing armies joined battle.
10. to adjoin;
    meet:
    His land joins mine.
11. Mathematics to draw a curve or straight line between:
    to join two points on a graph.

v.i. 

12. to come into or be in contact or connection:
    a place where cliffs and sea join.
13. to become united, associated, or combined;
    associate or ally oneself;
    participate (usually fol. by with):
    Please join with us in our campaign.
14. to take part with others (often fol. by in):
    Let's all join in.
15. to be contiguous or close;
    lie or come together;
    form a junction:
    Our farms join along the river.
16. to enlist in one of the armed forces (often fol. by up):
    He joined up to fight for his country.
17. to meet in battle or conflict.

n. 

18. a joining.
19. a place or line of joining;
    seam.
20. Mathematics union (def. 10a).

• Latin jungere to yoke, join
• Old French joign- (stem of joindre to join)
• Middle English joinen 1250–1300

join′a•ble, adj. 
Synonyms

• 1. link, couple, fasten, attach; conjoin, combine; associate, consolidate, amalgamate.
  Join, connect, unite all imply bringing two or more things together more or less closely.
  Join may refer to a connection or association of any degree of closeness, but often implies direct contact:
  One joins the corners of a mortise together.
  Connect implies a joining as by a tie, link, or wire:
  One connects two batteries.
  Unite implies a close joining of two or more things, so as to form one:
  One unites layers of veneer sheets to form plywood.
• 10. abut, border.

Antonyms

• 1, 12. separate, divide.