Correct spelling, explanation: the word lieu originates from Old French lieu, lou (meaning place, position, situation, rank; 10c.), and from Latin locum (nominative locus). The modern English spelling is exactly the same as the Old French one. You should remember to put the -i vowel before the -e, not the other way around. Remember that the only correct version of this word is lieu, not leiu.

Definition of lieu:
1. noun (archaic), place
2. part of the idiom in lieu of – instead of
In lieu of packing, I spent all Saturday cleaning my room.
I really wanted to go on a date with my girlfriend in lieu of staying home.

Collocations with lieu:
Some most commonly used collocations include: in lieu of.
They gave him a cash award in lieu of the promised plane ticket.
In lieu of pumpkin pie this year, we’ll be serving Twinkies.

Incorrect spelling, explanation: the word leiu is not correct, because this version doesn’t exist in any dictionary. This monosyllabic noun can be problematic to some English users due to the accumulation of vowels. If you’re not sure how to spell it, look at the etymology. You’ll know what it should be lieu, not leiu.