The Spanish verb 'secar' (meaning 'to dry') comes from the Latin verb 'siccare', which also meant 'to dry'. The Latin 'siccare' itself was derived from the Latin adjective 'siccus' meaning 'dry'. As Latin evolved into Spanish, the Latin 'sicc-' sound transformed into 'sec-', which is a common sound change pattern between these languages.

Some related Spanish words include 'seco' (dry), which is the adjective form, and 'sequía' (drought). You might also encounter 'secador' (hair dryer) and 'secadora' (clothes dryer), which are both derived from 'secar' and refer to machines that dry things.

While English 'dry' comes from a different root, there are some English words related to Spanish 'secar' through the Latin root 'siccus'. These include technical terms like 'desiccate' (to remove moisture), 'desiccant' (a substance used for drying), and 'siccative' (a drying agent, especially in paint or varnish). Notice how these English words preserve more of the original Latin 'sicc-' spelling compared to Spanish 'sec-'.