What is the line above a letter in spanish called?

Answer 1

There is the accent and the tilde

á the line above the a is an accent when used to add emphasis to a letter.

ñ the line above the n is a tilde

In certain words the line above a vowel is also called a tilde

él = Him/He . The line over the E is a tilde, not an accent even though it looks exactly like an accent. The difference is a tilde does not change the pronunciation. It is used to change the meaning of the word. el=the. él= he/him.

Answer 2

If you mean a little 'hook' rather than a line, it is called a 'cedilla'.

Although no longer used in Spanish (though it is in French and Portuguese), it was used in the past, and signifies the 'c' as an 's' sound when followed by an 'a', 'o' or 'u', when it would otherwise be a 'k' sound.

The word 'cedilla' does originate from Spanish, however: the diminutive of 'ceda' (nowadays 'ceta'), it meant a 'z' or a 'c' with a little tail or hook.

As it still does; but not in Spanish.

Note: The cedilla in Turkish has a "ch" sound.