“The distinction is a key one in structuralist semiotic analysis. These two dimensions are often presented as 'axes', where the horizontal axis is the syntagmatic and the vertical axis is the paradigmatic. The plane of the syntagm is that of the combination of 'this-and-this-and-this' (as in the sentence, 'the man cried') whilst the plane of the paradigm is that of the selection of 'this-or-this-or-this' (e.g. the replacement of the last word in the same sentence with 'died' or 'sang'). Whilst syntagmatic relations are possibilities of combination, paradigmatic relations are functional contrasts - they involve differentiation. Temporally, syntagmatic relations refer intratextually to other signifiers co-present within the text, whilst paradigmatic relations refer intertextually to signifiers which are absent from the text. The 'value' of a sign is determined by both its paradigmatic and its syntagmatic relations. Syntagms and paradigms provide a structural context within which signs make sense; they are the structural forms through which signs are organized into codes.”
(http://visual-memory.co.uk)

“In the case of film, our interpretation of an individual shot depends on both paradigmatic analysis (comparing it, not necessarily consciously, with the use of alternative kinds of shot) and syntagmatic analysis (comparing it with preceding and following shots). The same shot used within another sequence of shots could have quite a different preferred reading. Actually, filmic syntagms are not confined to such temporal syntagms (which are manifested in montage: the sequencing of shots) but include the spatial syntagms found also in still photography (in mise-en-scène: the composition of individual frames).”