Crossword Genius

It was in the church's interest (5)

Ross

I believe the answer is:

tithe

I'm a little stuck... Click here to teach me more about this clue!

'church's interest' is the definition.
The definition and answer can be both related to property as well as being singular nouns.
Perhaps there's a link between them I don't understand?

'it was in the' is the wordplay.
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'was in' becomes 'i' (I can't justify this - if you can you should believe this answer much more).
't'+'i'+'the'='TITHE'

Can you help me to learn more?

(Other definitions for tithe that I've seen before include "10 per cent levy" , "Regular payments" , "financial contribution" , "Ancient tax" , "Tenth of income given to church" .)

I've seen this clue in The Telegraph and The Globe and Mail.
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