What is "to broach to"

Broach \Broach\, v. t. [imp. & p. p. Broached; p. pr. & vb. n. Broaching.] [F. brocher, fr. broche. See Broach, n.]

1. To spit; to pierce as with a spit.

   I'll broach the tadpole on my rapier's point.
   --Shak.

2. To tap; to pierce, as a cask, in order to draw the liquor. Hence: To let out; to shed, as blood.

   Whereat with blade, with bloody blameful blade, He bravely broached his boiling bloody breast.
   --Shak.

3. To open for the first time, as stores.

   You shall want neither weapons, victuals, nor aid; I will open the old armories, I will broach my store, and will bring forth my stores.
   --Knolles.

4. To make public; to utter; to publish first; to put forth; to introduce as a topic of conversation.

   Those very opinions themselves had broached.
   --Swift.

5. To cause to begin or break out. [Obs.]
   --Shak.

6. (Masonry) To shape roughly, as a block of stone, by chiseling with a coarse tool. [Scot. & North of Eng.]

7. To enlarge or dress (a hole), by using a broach.

   To broach to (Naut.), to incline suddenly to windward, so as to lay the sails aback, and expose the vessel to the danger of oversetting.