"toward the front or a point ahead, forward; forward in time," late 14c., from on + -ward. The form onwards, with adverbial genitive -s, is attested from c. 1600. As an adjective, "moving on or forward," 1670s.
"in a position above and in contact with; in such a position as to be supported by;" also noting the goal to which some action is or has been directed; "about, concerning, regarding; in a position to cover;" as an adverb, "in or into a position in contact with and supported by the top or upper part of something; in or into place; in place for use or action; into movement or action; in operation," Old English on, unstressed variant of an "in, on, into," from Proto-Germanic *ana "on" (source also of Dutch aan, German an, Gothic ana "on, upon"), from PIE root *an- (1) "on" (source also of Avestan ana "on," Greek ana "on, upon," Latin an-, Old Church Slavonic na, Lithuanian nuo "down from").
Also used in Old English in many places where we now would use in. From 16c.-18c. (and still in northern England dialect) often reduced to o'. Phrase on to "aware" is from 1877.
adverbial suffix expressing direction, Old English -weard "toward," literally "turned toward," sometimes -weardes, with genitive singular ending of neuter adjectives, from Proto-Germanic *werda- (cognates: Old Saxon, Old Frisian -ward, Old Norse -verðr), variant of PIE *werto- "to turn, wind," from root *wer- (2) "to turn, bend." The original notion is of "turned toward."