count in

Related to count in: Count Me In

count in

1. To include someone or something in something, especially as participants are being recruited. Often used as an imperative. A noun or pronoun can be used between "count" and "in." Of course I want to go to the amusement park with you guys—count me in! Did you count Cathy in? She said that she'll make something for the potluck as well. Count this old tray in with the other things to be sold at the yard sale.
2. To introduce or signal someone or something with a countdown. A noun or pronoun can be used between "count" and "in." My favorite part of the night is counting in the new year with the entire city at once. The announcer will get the audience to count you in, at which point you'll drive your motorcycle down the ramp and over the row of parked cars.
3. To count (something) using certain sets of numbers. A noun or pronoun can be used between "count" and "in" to indicate what is being counted. The guard began counting the prisoners in fives and sending them to different parts of the prison for their work detail. I find counting in twos to be the quickest and easiest way when I have a large number of things to total up like this.
See also: count
Farlex Dictionary of Idioms.

count someone in (for something)

 and count someone in (on something);count someone in
to include someone as part of something. Please count me in for the party. Do count me in on it. Count in everybody who said they would attend.
See also: count

count something in

to include something in a count of something. Did you count the tall ones in? Did you count in the tall ones in the corner?
See also: count
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

count in

Include, as in Can all the members be counted in? or I'd love to come; count me in. [Mid-1800s]
See also: count
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • add in
  • all right
  • (one) never would have guessed
  • (mother) nature's (something)
  • (someone or something) promises well
  • a fast talker
  • a/the feel of (something)
  • (I) wouldn't (do something) if I were you
  • (have) got something going (with someone)
  • (you've) got to get up pretty early in the morning to (do something)