3D modeling terminology help

Hey everyone. I’m translating an article on character design into English and having relatively humble experience in 3d modeling I don’t know plenty of specific terms and slang. There’s one word, I can’t find an English equivalent for. What do you call the sort of artefact at the bottom of the picture which is highnighted with the red lines? Thanks!

UPDATE: this word is also used to describe this stuff with the castle model.

the top one doesnt really have a name that i have heard. maybe just bad interpolation from bad topology.

the bottom one is UV warping or stretching, this occurs when quads get triangulated on render.

i guess “interpolation” applies to both of these.

Probably distortion?

Could you maybe provide more context? Maybe the translated text around the word?.. I think that will improve your chances of getting the help you need dramatically.