22. The device of claim 15 , where the decision processor is further to: compare the coherence of the multiple terms in the sequence and the variation of the context terms to threshold values, and identify the sequence as the semantic unit based on comparing the coherence of the multiple terms in the sequence and the variation of the context terms to the threshold values.
15. A device comprising: a memory to store instructions; a coherence processor to execute one or more of the instructions to calculate a coherence of multiple terms in a sequence of terms, where the coherence processor calculates the coherence of the multiple terms in the sequence relative to a first collection of documents in which the sequence occurs; a variation processor to execute one or more of the instructions to calculate a variation of context terms in a second collection of documents that differs from the first collection of documents, where the variation processor calculates the variation of the context terms based on entropy of the context terms within the second collection of documents; a heuristics processor to execute one or more of the instructions to apply one or more predefined rules to the sequence, where the one or more predefined rules relate to defining sequence of characters as semantic units, and a decision processor to execute one or more of the instructions to determine that the sequence constitutes a semantic unit based on the coherence of the multiple terms in the sequence, the variation of the context terms, and further based, at least in part, on application of the one or more predefined rules to the sequence.