The Spanish verb 'valer' comes from the Latin word 'valere', which meant 'to be strong' or 'to be healthy'. Over time, the meaning evolved from physical strength and health to a more abstract sense of worth or value. This semantic shift from physical vigor to worth is quite intuitive - something that is strong and robust often has greater value or merit.

Several common Spanish words share this Latin root, including 'vale' (okay/goodbye), which is actually a form of 'valer' meaning 'it's worth it' or 'it's valid'. Another related word is 'válido' (valid), which maintains a connection to the original meaning of having strength or merit.

English speakers might recognize this Latin root in words like 'value', 'valid', 'valor', and 'valiant'. All these words retain some connection to the original Latin meaning: 'value' refers to worth, 'valid' means having merit or strength, 'valor' directly relates to strength and courage, and 'valiant' means brave or strong-hearted. The English word 'equivalent' also contains this root, literally meaning 'of equal value'.