Is there a difference between "subsidy" and "subvention"?

Is there a difference between subsidy and subvention? If yes, what is it? When should I use either?

Solution 1:

My advice is to use subsidy every time, the same as nearly everyone else does...

It's worth pointing out that the original sense of subvention was...

(OED) 1. An extraordinary tax levied by the state; the payment of this tax. Freq. in France, or in French contexts. Now hist.

...not that many people would be confused by that, since they probably wouldn't be familiar with the later meaning either.

Solution 2:

Looking at Dictionary.com, subsidy and subvention are explicitly listed as synonyms for each other; their definitions appear to be pretty similar, too. So for practical purposes, there's not much difference between them.

From personal experience, I would say that subsidy is more commonly used.

Solution 3:

Subsidy is the "English" word. Subvention is a word used in Latin languages such as French and Spanish, that has "crossed over" into (uncommon) English usage.