We don't have synonyms for tecum yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are cecum, tectum and tucum.
(n) :
Alternative form of tucum. [A fine, strong fibre obtained from the young leaves of a Brazilian palm (Astrocaryum vulgare), used for cordage, bowstrings, etc.]
(n) :
Alternative form of tucum. [A fine, strong fibre obtained from the young leaves of a Brazilian palm (Astrocaryum vulgare), used for cordage, bowstrings, etc.]