I'm thinking you're interpreting the zandar as a play on 斬鉄剣 (zantetsuken)? I can see why you'd do that, but I don't think it matches up with how Utsusemimaru's sword functions very well. We see it shooting lightning bolts and shocking people constantly, so thunder is clearly a literal property of the sword itself, not a figurative descriptor of the sword's greatness.
"Zan" by itself is often translated as "cut" for editorial reasons, not linguistic ones. "Zan" has a tendency to show up in situations where a long English word like "beheading" or "decapitation" would be really hard to read. Cut is usually substituted because it's very short and can be read easily in a lot of different contexts. If you simply read the "zan" kanji, its meanings have
no direct relationship to cutting. The kanji's meaning refers to beheading and killing pretty directly. This is the same kanji used to write 斬る, or "kiru," which means "to kill another human being" and connotes doing so with a sword, knife, or other bladed weapon.
Now, since 斬 is a kanji that pretty directly alludes to killing somebody with a sword, it certainly appears as part of some verbs that you could translate as "cutting" in English. But these verbs usually have violent connotations, and refer in some specific way to using blades to hurt or kill someone (or something). "Cut" in English is a more basic word and doesn't automatically connote violence in quite the same way (unlike, say, "stab" or "rip").