English has countable nouns and uncountable nouns.
But I sometimes see the use of article with uncountable nouns
in a sentence like 'we have an utmost importance'.
Here is an example.
I bring up, based on these three observations, a challenge with an utmost importance: we must radically change our fundamental perspective to grasp the world.
Source: An Ecological Vision of the World: Toward a Christian Ecological Theology for Our Age
by Hyun-Chul Cho. Gregorian Biblical BookShop, 2004.
How do we know when we use an article with uncountable nouns?
Best Answer
An utmost importance is not natural English. It would not surprise me if the author of your example is not a native speaker.
The issue of English having count nouns and mass (or non-count) nouns is a poor way to talk about nouns in English.
A better way is to say that nouns can be used as count nouns, non-count nouns, or both.
Some nouns in English can be used as both count nouns and non-count nouns. Let's look at freedom.
It can be used as a count noun:
It can also be used as a non-count or mass noun:
Ultimately, what decides whether a noun can be used as count, non-count, or both is the community of English speakers. Some nouns used only as mass nouns today were once used as both.
But importance is used only as a non-count noun in today's English.
As for your actual question:
You cannot use the indefinite article with a singular noun used as a non-count noun.
The following is ungrammatical:
You can say:
because a cappuccino is conceptualized as a serving of cappuccino.
You can say:
because a coffee is conceptualized as a type of coffee.
You can use the definite article with singular or plural count and non-count nouns.