Which part of speech that modifies an adjective in these contexts?

Question

I'm wondering whether the words such as "pitch" and "dark" can be considered as an adverb. I have looked up in OALD that both words can't be adverbs since they are not registered in the dictionary (unless the dictionary doesn't put them in the list for a certain reason).

Let's see some examples here:

Can you see anything? *No, it's pitch dark *.

I have a dark blue patch on my left eye because I've got Amblyopia.

As you can see there, I believe, pitch dark is an adjective phrase and a dark blue patch is a noun phrase. I also believe that both pitch and dark modify the adjective in front of them since, for instance the second one, dark can't be modify patch. I'm thinking of this way: The patch has blue color. How is the blue? The blue is dark. So, what are those words exactly? Can they be considered as an adverb?

The reason I'm asking this question, because I'm learning Czech and struggling with the difference between tmavě and tmavé. Someone told me that the first one is an adverb, whilst the second one is an adjective. They also gave me examples, and for convenient reason I include the translation that I got from Google Translate.

• Tmavě svítící paprsky. (Dark glowing rays.)

• Tmavé kouty. (Dark corners)

From the translation, I imply that those are noun phrases, therefore dark glowing and dark are adjectives. Which is why I'm questioning which part of speech dark is in those contexts in English.

Answer 1

Some people would say that any word that modified an adjective was an adverb; I prefer to reserve the term "adverb" for only those words that are so categorized according to their part of speech.

In your first sentence, I'd consider "pitch" a noun (not an adverb!) functioning adverbially to modify the adjective "dark". Similar constructions appear in the phrases "rock solid" and "Minnesota nice".

In your second sentence, I'd consider "dark" to be an adjective modifying the noun "blue". The entire noun phrase ("dark blue") functions adjectivally to modify the following noun ("patch"). Similar constructions appear in the phrases "electric battery vehicle" and "soft shell crabs".

I can't comment on the Czech; other languages often have very different rules regarding parts of speech, syntax, etc.

Answer 2

The first important thing to remember is that the names of colours are used in different ways. Most of the time, they are adjectives because they describe something else (eg 'blue car'), but as names that identify specific colours they are of course also nouns.

"Dark" is not a colour. It is mostly used as an adjective. You could add it to a colour, for example, 'dark blue'. When used as the specific name of a colour, "dark blue" would be a compound noun, but if you used it to describe something else (eg 'a dark blue car') then it would be a compound adjective. In other contexts, it could just be viewed as an adjective and a noun distinctively. Context is key.

But the second important thing to note is that "dark", when used as a noun, often means nighttime. For example, we might say "after dark", referring to the time of day when the sun has gone down. So this is a key way that 'dark' is very different from colours.

"Pitch dark" would not normally be used as a colour. Darkness is an absence of light, and therefore a condition in which it is not possible to see colour. "Pitch black" is often used the same way - to refer to a very dark condition. However, it could also be used as the name of an extremely dark shade of black. "Pitch" is actually a noun - it is a resinous product derived from tar - but used as an adjective in this kind of context to emphasise the darkness of the black, similar to the way we say "sky blue".