In 1989 the term was "free software" (the term "open source" had not yet been applied to software). It was pretty unknown at that point so we had to explain it to people.

In more than once case I sat in a conference room and was told by some exec that I (or we) was a fucking idiot while he (always he back then) handed me a P.O. or signed contract for $1MM. Needless to say I didn't care what they called as as long as they continued to pay.

Having to invent a whole new business model going into a mature market is hard and we worked hard at it. Also I had to write the first blanket assignment, the GNU library license (dynamic linking was Gilmore's great idea though), the fork-and-steering committee model (google for my message about splitting of GCC into egcs -- forking was super super controversial back then and was assumed by most people to be doom)... yes, fun times.