This paper reports the results of a preliminary experiment on the detection of semantic variants of terms in a French technical document. The general goal of our work is to help the structuration of terminologies. Two kinds of semantic variants can be found in traditional terminologies : strict synonymy links and fuzzier relations like see-also. We have designed three rules which exploit general dictionary information to infer synonymy relations between complex candidate terms. The results have been examined by a human terminologist. The expert has judged that half of the overall pairs of terms are relevant for the semantic variation. He validated an important part of the detected links as synonymy. Moreover, it appeared that numerous errors are due to few mis-interpreted links: they could be eliminated by few exception rules.