Is 'La cabeza' a side of a coin in Spanish as well?
Aslo, how do you say 'tails' then?
It depends on the region, but some translations for what we call "heads or tails" are "cara o cruz," "cara o sello," and "águila o sol." You can see a full list here: http://es.wikipedia.org/wiki/Cara_o_cruz#Nombres_en_cada_pa.C3.ADs
Can it be used in cases like "head of the family", "head of the department", etc?
"The heads" also refer to the toilets on a ship. Can this usage transfer to Spanish. That is the use of the words not the toilets. :)
The tractor unit... I know what a tractor is but not necessarily a tractor unit.
Very interesting, thank you!
I also had no idea what a 'tractor head' was in English, but for anyone who can't get the link, it's the front part of a lorry (or truck) in which the driver sits.
Oh! I wrote my comment (below) before I saw yours, lol! Great minds think alike, ha, ha!