I
n.
1) on ~ ('ready to be drawn') (beer on ~)
2) on ~ ('available'); ('imminent') (what's on ~ for tonight?)
3) see faucet
II
v.
1) ( d ; tr. ) ('to ask') to ~ for (to ~ smb. for information)
2) ( D ; tr. ) to ~ on ('to strike lightly') (to ~ smb. on the shoulder)