1. [v]  fall down, as if collapsing
2. [v]  cause to topple or tumble by pushing

TOPPLE is a 6 letter word that starts with T.

1. \Top"ple\, v. i. [imp. & p. p. {Toppled}; p. pr. & vb. n.
   {Toppling}.] [From {Top} summit.]
   To fall forward; to pitch or tumble down.
   
         Though castles topple on their warders' heads. --Shak.
   
   

2. \Top"ple\, v. t.
   To throw down; to overturn.
   
         He topple crags from the precipice.      --Longfellow.