[Idiom] pay by installment or installments?

[LiuJing]

Which phrase is proper, to pay by installment or to pay by installments?

Thank you.

 

[emsr2d2]

Which phrase is proper, to pay by installment or to pay by installments?

Thank you.

In BrE, it's "pay by (or in) instalments".

Note the BrE spelling too. Only one "l" in instalments. I believe there are two in the American spelling.

 

[LiuJing]

In BrE, it's "pay by (or in) instalments".

Note the BrE spelling too. Only one "l" in instalments. I believe there are two in the American spelling.

Thank you, emsr2d2. You have been very helpful.
Before the post was created, I tried several google searches holding the belief that to pay by installments should be the right one, but found some credible native-speaker-run websites adopted both ways, like : Pay by installment - Imaginative Traveller

OCAD - Students - Tuition & Fees - Paying by Installment

Do you think they are errors?

 

[emsr2d2]

Thank you, emsr2d2. You have been very helpful.
Before the post was created, I tried several google searches holding the belief that to pay by installments should be the right one, but found some credible native-speaker-run websites adopted both ways, like : Pay by installment - Imaginative Traveller

OCAD - Students - Tuition & Fees - Paying by Installment

Do you think they are errors?

Well, if you think about it, it wouldn't make any sense for it to be in the singular. If you "pay by instalment" then you are paying one instalment, therefore you are paying the whole fee at one time! That would defeat the object.

Logically, you pay the fee over a period of time and the fee is broken down into a certain number of instalments.

I will stick to my guns on this one and say it should be in the plural, no matter (as usual) what you may find on Google!