Same entry elsewhere: see the references at Photius lambda265 Theodoridis. The neuter plural headword should be lh/mmata "premisses, sayings". (On this difference of spelling cf. Alexander of Aphrodisias, under lambda 441.)
The "prophecy" meaning is LSJ s.v. lh=mma IV, "burden or commission of prophecy", exemplified by several passages in the Septuagint; and as Theodoridis notes, the lexicographers' plural is likely to be quoted from Lamentations 2:14.