The process should be "search in a bilingual dictionary" followed by "check in a regular dictionary" or "broaden your search with a thesaurus".
If you know the word in your native language (or in any other language) then a bilingual dictionary is the right tool to start with:
I know the word in French is "maison", what is the word in English.
This can be supported by a conventional English-English dictionary, which can help you decide between "house", "home", "dwelling", "domicile", or any other word which can be a translation for "maison" in some context.
If you don't know the word in your native language, then it probably doesn't exist in English.
What is a specific word for a drinking vessel made out of metal? Like "glass" but for metal. Not "cup" because that could be made out of plastic or pottery.
There are cases where a word exists in English, but doesn't exist in some other languages. For example, "sibling" doesn't have a convenient short translation in French. But if you don't know the word in English, and have been able to work around the meaning in French, you probably don't need to ask "How to a say 'brother or sister' in one word." The question won't even occur to you.
It is practically impossible to have a true reverse dictionary. There are so many ways that you could define "house". Should it be "Place where people live" (but that could also be a home, a flat, a dwelling, a town, a city, etc." Or "A place with windows and doors" (but churches, offices, shops, etc have windows and doors), or is is "a building with windows and doors" or "a construction with windows and doors".
A thesaurus can be helpful if you know some similar words, but want a specific one. A thesaurus search on "brother" will find "sibling". A thesaurus search on "cup" will find many words, but none that means "a metal drinking vessel" (suggesting that no such word exists).
Finally, if you have looked up the word in a bilingual dictionary, but its translations are inadequate, or you know that the word should exist in English, even though it doesn't exist in you native language, then a good thing to do is to post a question to English Language Learners Stack exchange. But be sure to give a clear summary of your prior research, and the reason that the bilingual dictionary doesn't help you.
crosswordafter describing in a succinct way the word I'm really looking for. Another method is looking up a more general or related word and looking at the synonyms section either on lexico.com, or directly on Google, and then slowly narrowing it down from there.