a thingy for the whatsit

Reader's Digest 6月号のJust Snap It For the Recordと題された記事からの抜粋です。
Need help with your DIY project?
Take a pic of the problem to avoid "a thingy for the whatsit" explanations at the store.
"a thingy for the whatsit" は多分「あれ」の事を言っているのだと思いますが、まず、 "thingy" を辞書で引きます。
・Macmillan Dictionary: used for referring to something when you do not know or cannot remember the name of it: Hand me one of those red thingies over there.
・Cambridge English Dictionary: sometimes used if you can't remember someone's or something's name: Ask thingy over there, he'll know.
そうすると "whatsit" も同じような意味でしょう。
・Cambridge English Dictionary: any object or person whose name you have temporarily forgotten or do not know: Where's the whatsit that you change channels with?
・Collins Dictionary: a thing the name of which is unknown, temporarily forgotten, or deliberately overlooked: Also comes to Lewis Department store and calls my brother Sniffer a useless whatsit for pulling his beard off.