1. A computer-implemented method comprising: obtaining a resource that includes a first term that includes at least a first word and a second word; identifying a second term that (i) includes at least a third word and a fourth word, and (ii) that is indicated as a substitute term for the first term; storing, as a first entry in a search index, (i) data referencing the first word included in the first term, and (ii) data referencing the resource; storing, as a entry in the search index, (i) data referencing the second word included in the first term, and (ii) data referencing the resource; storing, as a third entry in the search index, (i) data referencing the third word included in a second term that is indicated as a substitute term of the first term, (ii) data indicating that the third word included in the second term is a part of a substitute term and does not actually occur in the resource, (iii) data relating to a quantity of words in the first term, (iv) data relating an order of the third word within the second term, and (v) data referencing the resource; and storing, as a fourth entry in a search index, (i) data referencing the fourth word included in a second term that is indicated as a substitute term of the first term, (ii) data indicating that the fourth word included in the second term is a part of a substitute term and does not actually occur in the resource, (iii) data relating to a quantity of words in the first term, (iv) data relating an order of the fourth word within the second term, and (v) data referencing the resource.