I have already complained about the use of boom and kaboom. This does not make it better.
Why can't we just use the names that the symbols actually have?
Because the symbols don't actually have names. No where in the manual does it say anything such as 'a filled in explosion is called a hit/boom/explosion, while a empty circle explosion is called a crit/kaboom/empty circle explosion.'
And as such, the instinct is to call the filled in explosion a "hit." However, the term hit is already used in the game to describe what happens when either Blount shoots, or there are uncancelled <booms> and/or <kabooms> after any <evades> are applied.
Therefore, calling a filled in explosion a hit is bad and incorrect. Take for example the following statement "Arrgg, I hate tie fighters. I got 2 hits and a crit on it but the thing still didn't die. Determination is OP." Now, is the person complaining that he rolled <boom boom kaboom> and it didn't kill the TIE fighter (which is logical, it's likely to have rolled at least one <evade>, and from the context Determination discarded the face up damage card), or did he have 3 separate attacks connect and do damage, but due to Determination getting rid of the faceup damage, the TIE is still alive?
You see, it's ambiguous to call a filled in explosion a hit. And since there is no defined name, going with <boom> at least differentiates it from hit.
Check the FAQ (V3.02), page 5, 2nd column, 1st section,
When attacking, players may spend focus tokens or target locks and elect not
to modify any attack dice. When defending, players may spend focus tokens
and elect not modify any defense dice and may spend evade tokens to add
evade results in excess of the number of hit and critical hit results.
Also check comment #22