The Spanish word 'comentario' (meaning 'commentary') comes from the Latin 'commentarium', which meant 'a collection of notes or explanations'. This Latin word was formed by combining the verb 'commentari' ('to meditate or reflect upon') with the collective suffix '-arium'.

Going further back, 'commentari' developed from 'comminisci' meaning 'to imagine or devise'. This verb itself was created by combining two Latin elements: the prefix 'con-' meaning 'together' and 'mens' meaning 'mind or thought'. So etymologically, a 'comentario' is literally something devised by putting thoughts together!

Some related Spanish words include 'mente' (mind), 'mental' (mental), and 'mentalmente' (mentally), all of which share the Latin root 'mens' (mind). The connection is clear - while 'comentario' refers to thoughts put together in written or spoken form, these related words all deal with the mind and thinking.

English speakers can easily connect 'comentario' with the word 'commentary'. Both come from the same Latin source 'commentarium'. Other related English words include 'comment', 'mental', and 'mention', which all trace back to the Latin root 'mens' (mind). This shared etymology explains why all these words relate to thinking, speaking, or expressing thoughts.