Idioms with the word ONE. Vocabulary Advanced

In English there  are  lots of idioms with the word ‘one’.

A  one-off  (noun and adjective) : something that happens only once…. una vez en la vida…

One at a time : individually, one by one or one after one. No habléis todos a la vez… de uno en uno,… cada vez uno….

As one (man)  : to do something together, simultaneously

Back to square one :  back to the beginning ; to start again: empezar de cero. (también to start from scratch)

(to look after) number one : to look after or think about oneself: si no te cuidas tú mismo…. Quién te va a cuidar…

a million and one  : very many

a million to one  : hardly any chance at all… una entre un millón, ninguna posibilidad.. doesn´t stand a chance.

One and only :  the only person or thing ; something unique

One and the same : same as, identical  

One for the books : an event to be remembered. Va a ser recordado…

One for the road : the last drink before leaving. Tómate la espuela… la penúltima…