PIE base ‘to perceive, see’. See also *weid- ‘to see, know’, root of vision, and *wer-³ ‘to perceive, watch out for’, root of theory.

Pokorny says that this PIE root is identical with *sekʷ-¹ ‘to follow’, where see might mean, etymologically, ‘follow with the eyes’. However, the OED finds this “involves a hypothetical sense-development which it is not easy to accept with confidence”.

As there are words outside Germanic that have a similar meaning and morphology, Watkins also splits the Pokorny root into this and sekʷ-³ ‘to say’, which is not generally accepted.

With this proviso, other derivatives might include see and sight.

[Pokorny *sekʷ-2, ‘to see, show; to speak’, pp. 897–898.]