I was proofreading an email I'm sending at work, and noticed that I'd written "intsead". The odd thing is that Outlook hadn't red-squiggly-underlined it as a spelling error.

I have to believe (don't I?) that somehow "intsead" got into my custom dictionary at some point. So I should (shouldn't I?) go find this word in one of Outlook's spelling dictionaries, and eliminate.

But so far I've found only one custom dictionary, and "intsead" isn't in there. I have Outlook 2010 on that machine; I started with the main Outlook window, went to File, Options, chose the Mail tab, clicked the button for "Spelling and Autocorrect...", then "Custom dictionaries...". CUSTOM.DIC is the only one; I selected "Edit Word List". If "intsead" isn't in there, why is Outlook accepting it as a correct spelling?