Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ter-dĕcĭes or -ĭens, adv. num., thirteen times: quem circulum luna terdecies in duodecim mensibus percurrit, Vitr. 9, 4: respirare, Juv. 14, 28: HS. terdeciens, Cic. Verr. 2, 3, 80, § 184: binas terdecies, semel quaternas, i. e. thirty, Aus. Ep. 7, 32.