Definition of trigonometrical in English:

trigonometrical

Pronunciation /ˌtriɡ(ə)nəˈmetrək(ə)l/ /ˌtrɪɡ(ə)nəˈmɛtrək(ə)l/

adjective

See trigonometry

‘But there were algebraic, trigonometrical, and simple Pythagorian solutions offered, too’
  • ‘Astronomy, time-keeping and geography provided other motivations for geometrical and trigonometrical research.’
  • ‘Rather than using geometrical methods, as Ptolemy had done, al-Battani used trigonometrical methods which were an important advance.’
  • ‘He studied algebras and published papers on trigonometrical series.’
  • ‘It is perhaps surprising that the second most important trigonometrical function during the period we have discussed was the versed sine, a function now hardly used at all.’