I find it pays not to be too pedantic, as it really depends on who you are talking to. If you say 'partial albino' then people know what you mean - a bird with white patches. If you say 'albino' people think of a pure white bird with pink eyes (no pigment anywhere), and if you say 'leucistic' then most people think of a pale, washed out bird where the colouring is diluted. Scientifically, a bird with white patches is, in fact, leucistic. Just as leucistic as a washed out bird. Albino refers only to things which have two recessive genes and, therefore, no pigment anywhere. As such, you cannot be 'partial albino' as you do not have both recessive genes. As leucism is a spectrum between white and normal, any odd white feathers are leucistic. This could be genetic, or indeed possibly from infection/trauma. Leucism is kind of the opposite of melanism.
Your pipit seems to be leucistic.