Minecraft wiki entry for TNT, associated text: "TNT" stands for Trinitrotoluene. The Preferred IUPAC name, however, is 2,4,6-trinitrotoluene.
The use of sand in the crafting recipe references dynamite, a different high explosive than TNT, consisting of nitroglycerine mixed with diatomaceous earth (which is mostly silica, the same chemical compound as yellow sand).
Although flint and steel cannot light fires in Adventure Mode, it can still ignite TNT.
It takes 19.75 blocks to fall for it to reduce the timer for one second.
Although primed TNT normally gets caught in cobwebs, TNT propelled fast enough flies through them without slowing down at all.
It is slightly smaller than a full block when activated, as with all entity versions of blocks (see shulker).
Using flint and steel to ignite it sets it off at once, but fire must burn it for many seconds before triggering.
In Pi Edition, TNT by default doesn't do anything, but when set to data value 1, it ignites when broken.
The longest fuse time of TNT is 27 minutes and 18.35 seconds, or 32,767 ticks.
Attempting to ignite TNT while sneaking results in the block being lit on fire, rather than the TNT becoming primed.
Standing behind blocks during an explosion dramatically reduces knockback and damage from the explosion.
TNT does not damage the player on peaceful difficulty, however, it does break blocks and damage entities.
The TNT fuse sound uses the same sound file as when a creeper is primed, but it is played at a higher pitch when the TNT is primed.