These should have a newline instead of a colon:

    term 1
        Definition 1.

    term 2
        Definition 2, paragraph 1.

        Definition 2, paragraph 2.

    term 3 : classifier
        Definition 3.

    term 4 : classifier one : classifier two
        Definition 4.

Right now, `return the value at the data point closest to` is being interpreted as the classifier, and then `the point of interpolation...` is interpreted as the definition.