Once you get past the thin, dry, brown skin, the onion is composed of many layers. We often use onion or peeling an onion as a metaphor for something that has many layers. For example, there is a system for browsing the web anonymously called Tor. Tor is an acronym for The Onion Router, which refers to the fact that all communications are wrapped in many layers of security.
Onion can be treated as a countable or uncountable noun, so either might be used. (if something is cooked or sliced it might tend to become an uncountable/mass noun).
In French, there's the expression occupez-vous de vos oignons which means "mind your own business" in English but can be literally translated as "take care of your onions". Know your onions howe...
It really depends on the onion and what exactly you are trying to convey to the listener. An onion might be strong, mild, aromatic, tear-inducing, acidic, salty, spicy, sweet, bitter, sour, or flavorful.
word choice - How do you describe the taste of an onion? - English ...
Today I came across a sentence in The Daily Star prices of locally grown onion rose yesterday for the lack of availability. I know onion is countable.Therefore,it should have been locally grown ...
Contrary to what you learned in school, there are more than just vowels and consonants. In words like 'onion', the i serves as a semi-vowel, or glide. This is represented in IPA as /ˈʌn jən/ and the letter i represents the /j/ sound, which is the same sound as at the start of the word "yes".