Statements with implicit meanings are often used in physics. The paper deals with the importance and the possible consequences of such a practice, in the specific realm of constants. The question in fact is what meanings are triggered by common statements containing the word 'constant' and the ensuing difficulties which result. The word 'constant' may evoke a range of meanings with the two following notions at each end: number, the essential being its numerical value; and a constant function of certain variables, the important thing now being the listing of these variables. In this way constants appear as a particular aspect of functions of several variables. The results of an investigation among French and Belgian students at the beginning of their studies at University are reported and analysed. The usual interpretation of the word 'constant' is biased towards the numerical aspect of this notion, at the expense of its functional meaning. Lastly a plea follows for using exercises of 'text criticism' as pedagogical tools in teaching.