By analogy with centre/theatre/etc, you mean? FWIW OED has "trimester" and says "trimestre" is "obs., rare".
I have seen it spelt "trimestre" on various pregnancy forums, but given that they tend to be populated by people who can't even spell "pregnant" I didn't pay much attention!
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Date: 2010-11-19 04:29 pm (UTC)I have seen it spelt "trimestre" on various pregnancy forums, but given that they tend to be populated by people who can't even spell "pregnant" I didn't pay much attention!