I write educational resources about Japanese. In my explanations, I try to avoid using overly technical terms so as to avoid scaring my readers, who tend to be people without a linguistic background.
I think many people who have studied a foreign language have probably heard the term "diphthong" before, but I'd wager that not many casual learners actually understand clearly what it is. For that reason, I've taken to using the term "gliding vowel" and illustrating what it is by using the English "long o" sound.
From my searching online, it appears that "gliding vowel" is an accepted synonym for "diphthong." I prefer the term "gliding vowel" because it is possible for an uninitiated person to instantly imagine what it probably means. The term is clear and memorable.
The possible critique I can see against this term is that it is similar to "glide," which I do understand indicates something different. (And, full disclosure, in the past, I have incorrectly have called gliding vowels glides, an error I am correcting as I revise my materials.)
I am trying to strike a balance between technical accuracy and approachability. Is "gliding vowel" a term that a linguist would take issue with?