As adults, we know the term "identical twins" means that the twins look the same.

The McClure twins did NOT know this, but we'll give them the benefit of the doubt because they are really little.

Lexi's answer wasn't far off, though, when she said that the term meant that they were adorable.

WATCH: Twins realize they look the same

Their epic mirror staredown showed that.

But after they got through the staredown, Lexi got a little worried when she realized Ava was a minute older -- how can they be identical if they're not born at the same EXACT time?

"I wanna grow," she said with a pout.

But "big" sister came to her aid to cheer her up with a measuring contest, which took a turn on her as Lexi was a little bigger.

Lexi switched roles and comforted her minute-older sister, showing these sisters, like many, have a strong relationship.