Correct spelling


Correct spelling, explanation: generally we add suffix -ible to words that come from Latin, and since reverse derives from Latin reversus, then reversible is the correct form, not reversable. The mistake may however come from the fact, that it is also said that suffix -able is generally added to the complete root words, but it doesn’t apply here. Reversible is therefore the only correct spelling.

Definition of reversible:
adjective, able to be reversed; also: one that has two sides, for example piece of clothing
This substance can cause reversible change on the skin.
The coat is reversible and can be worn inside out as well.

Incorrect spelling


Incorrect spelling, explanation: reversable is a mistake, because suffix -able is generally added to words, which don’t derive from Latin, while reverse is a Latin-rooted word. Therefore the correct form is reversible. Reversible is the correct form, because reversus is a Latin word, which means suffix -ible applies in this case.