Hate to appear to be beating a dead horse, but I do believe you are correct in stating that a number of Noront Forum posters refer incorrectly to the TSE main board as the "big board". But Colombo is also correct in stating there is only one "BIG BOARD" and that has always been the New York Stock Exchange.
If ALL NOT forum posters used this term to mean the TSE, no real problem. But, unfortunately some know what the "BIG BOARD" is, and therein lies an area of of confusion. Call any exchange by any knickname you like (it's a free country, eh?), but if you wish to be clear, best to follow convention.
(Well meant, if sounding a bit pedantic)
Best wishes to all NOT forum enjoyers!
O.F.