Where does the word bailout come from?


Bailout has become closely associated with the idea of financial rescue -  to bail out the banks/Cyprus. But the word has many subtle usages - and two spellings!
1.  bail/bale is to abandon abruptly as in making an emergency exit from an aeroplane in a parachute. 
2.  to bail out is to remove water from a leaky boat. 
3. It is now more common to use bail  in a figurative/metaphorical sense:
The minister has bailed on the government's housing policy (announced his opposition).
The pilot bailed out
The actor bailed on the script (stopped reading his lines with any show of conviction) 
4. 'Bail out' is also used metaphorically but usually with a closer connection to the literal meaning: The pilot bailed out of his plane.
5. The noun is sometimes spelled as one word: bailout.

6. There is a dispute over the spelling of bail and bale - bail is probably used more frequently but both are allowed by most dictionaries.