la 1
/lah/ , n., Music.
1. the syllable used for the sixth tone of a diatonic scale.
2. (in the fixed system of solmization) the tone A. Cf. sol-fa (def. 1).
[ 1350-1400; ME; see GAMUT ]
la 2
/law, lah/ , interj. Archaic or Dial.
(used as an exclamation of wonder, surprise, etc.): La, sir, how you do go on!
[ bef. 1150; ME, OE; weak var. of la LO ]