I was surprised to hear this, since Khomeini was so commonly referred to as "Ayatollah" in the media. Wikipedia[0] still says his title was "Grand Ayatollah," but what appears to be his official memorial web site[1] calls him "Imam Khomeini."

(Unrelated, but interesting to consider he was only in power for about 10 years, and has been dead for more than 30.)

[0]: https://en.m.wikipedia.org/wiki/Ruhollah_Khomeini

[1]: http://en.imam-khomeini.ir/en/n3733/Imam/Who_is_Imam_khomein...