lo
exclamation /ləʊ/
  /ləʊ/
(old use or humorous)Idioms - used for calling attention to a surprising thing
- An extra skittle was added and, lo, tenpin bowling was born.
 
Word Originnatural exclamation: first recorded as lā in Old English; reinforced in Middle English by a shortened form of loke ‘look!’, imperative of look. 
Idioms 
lo and behold 
- (humorous) used for calling attention to a surprising or annoying thing
- As soon as we went out, lo and behold, it began to rain.