That could be either of the two biggest digits on your feet;
or when spelled thusly: Big T.O.E. refers to the Big Theory Of Everything, which by it self, is self explanatory.
1. OUCH!!!!!!! I crushed my big toe!
2. The Big Theory Of Everything is a complicated mess of facts, figures and things totalling the sum 42.
Bigtops is a special kind of weed, provided exclusively by Dutch coffeeshop 'The Stepping out'. Bigtops is known by its cutting edge smell and its ability to blazepeople out of their skulls. It is not recommendable to smoke 'the nice biggins' whilst not an extreme expert in puffing the magic dragon. Side-effects may vary from nausia to certain deaths.
That nice biggins really did the trick, i'm high as a m*therf*cker!