Sentence:  Because the CES-D items are ordinal in nature (i.e., in our case a four-point response scale, and hence not continuous), a <WSD>polychoric</WSD> covariance matrix was used as input for the analyses. 
Meaning of the word marked with <WSD> tags:  Of or pertaining to the relationship between two latent variables, each assumed to have a normal distribution and associated with an ordinal variable.