"fil" in baptism record?

[Sue from Southend]

Thomas and Joan Bown are baptised 9 Apr 1798 in Horsley, Gloucs. With no date of birth -
http://interactive.ancestry.co.uk/47...nSearchResults
They are bracketed together with the word "fil". I assumed that they were twins but on the previous page twins are noted as such. Other baptisms on these two pages show two children bracketed together and dates of birth noted and in another example three children bracketed together with "fil" and no d.o.b.

So do we think that Thomas and Joan are twins or just siblings baptised by an inconsistent Vicar?