What Is a Subordinate Clause?

By Mark Nichol

A subordinate clause, also called a dependent clause, consists of information to be combined with a main clause to form a single sentence. It resembles a main clause except for the presence of a subordinate conjunction or a relative pronoun, either of which renders it subordinate. Here are some guidelines about its use.

To convey two thoughts, you can write, for example, “I went to school. I was feeling ill.” However, this construction offers no clue to the relationship between the two statements. To clarify that you wish to explain that you attended school in spite of your illness, you can combine the two thoughts into one, but you must include a conjunction that conveys the subordinate status of the second statement: “I went to school, although I was feeling ill.” (The subordinate clause can also come first: “Although I was feeling ill, I went to school.”) Other common subordinate conjunctions include because, until, and when.

Note that no other internal punctuation can substitute for the comma: The subordinate conjunction is not necessary in the following sentence, because the semicolon indicates that the sentence consists of two main clauses: “I went to school; I was feeling ill.” (You could also separate the statements with an em dash or enclose the second sentence in parentheses.) However, without the subordinate conjunction, the relationship between the two statements is not expressed. The sample sentence suggests that you went to school because you were feeling ill, not in spite of your illness.

To combine the thoughts “I went to school even though I was ill” and “Going to school when I was ill was not a good idea,” you can substitute the subject of the second statement with a relative pronoun: “I went to school even though I was ill, which was not a good idea.” (Other relative pronouns include that, who, and whose.)

Because this type of subordinate clause incorporates a relative pronoun, it is also called a relative clause. Note that you must take care when constructing some relative clauses, because the meaning can differ depending on whether the relative pronoun is preceded by a comma.

For example, “We got a ride with our friends who were also going to the movie” implies that among all our friends, we rode with those who were also going to the movie. However, in “We got a ride with our friends, who were also going to the movie,” the relative clause refers to a particular group of friends and makes no distinction between them and other friends because it makes no reference to other friends at all.

In the first sentence, the relative clause is a required part of the sentence and thus is called an essential relative clause. In the second sentence, it is not required (you can omit the relative clause and simply write, “We got a ride with our friends”) and thus is called a nonessential relative clause.

When a clause follows and expands on a verb (or, sometimes, an adjective or another adverb), it can also be called an adverbial clause. For example, in “They laughed because the dog was chasing its tail,” the phrase after laughed explains the reason for the laughter. However, a sentence such as “They laughed at the dog” contains not an adverbial clause but an adverbial phrase, because “at the dog” is not a clause; unlike “the dog was chasing its tail,” it does not constitute a complete thought.

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6 Responses to “What Is a Subordinate Clause?”

  • Stefano

    Dear Mr Wood, “Ich weiss nicht, dass Sie mir sagen!” does not mean anything in German — nor in English, if you translate it: “I don’t know that you’re telling me”

    The sentence might work with “was” (what). “I don’t know what you’re telling me”, and that happens to sum up how I feel about this post of yours…


  • Dale A. Wood

    “Other common subordinatING conjunctions include” THAT.
    Note that the proper terminology is “subordinating conjunctions”. Both my mother and all of my other English teachers have always called them this.

    In this article, Mr. Nichol calls “that” a relative pronoun, but never in my life have I ever heard “that” referred to as a relative pronoun. The words corresponding to “that” in other Indo-European languages are also subordinating conjunctions, such as the word “dass” in German.
    “Ich weiss nicht, dass Sie mir sagen!”

    Mr. Nichol might be getting confused by the fact that another use of “that” is as an indicative pronoun, such as is used in pointing at people, places, and things. The indicative pronouns include {this, that, them, these, and those}. In the dialect of places like New Jersey, four of these words are pronounced {dat, dem, dese, and dose}, and that set is indicative of a person who comes from New Jersey and maybe Delaware, Staten Island, and maybe some other parts of New York City (Brooklyn?). The word for this sort of thing is “shibboleth”.

    The list of relative pronouns that was given in this article was notable in being VERY sparse. Here is a better one: {who, WHOM, which, whose}
    In German, these are closely-related words that all start with “w”, such as {wie, wer, wem, wen, welch, was}. In both English and German, there is a great amount of overlap between the relative pronouns and the interogatory pronouns. That is the way that it is.

  • Mark Nichol


    Most subordinating conjunctions require no preceding comma (for example, consider sentences with before, if, or when), but those such as although and whereas that precede a contrasting statement should be preceded by one.

  • Mark Nichol


    I agree. The subordinate clause should be at the head of the sentence.

  • Dermot McCabe

    In the sentence “I went to school, although I was feeling ill.” is the comma correct or is it optional where the meaning is clear. Your tips are so helpful. Thank you.
    Dermot McCabe

  • thebluebird11

    Re: “I went to school even though I was ill, which was not a good idea.”
    I don’t like this revision. It makes it seem as though being ill was not a good idea. OK, being ill is NOT a good idea, but the point of the sentence is that going to school (while ill) was not a good idea. I think a better revision would be “Although I was feeling ill, I went to school, which was not a good idea.”
    I guess to some people this might seem overly picky, and certainly in casual conversation nobody would blink an eye and the speaker’s intention would be understood. But in written communication, we have the luxury of being able to revise and bring forth clarity, so I say take advantage of that and be clear!

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