now vs till

now

conj
  • Since, because, in light of the fact; often with that. 

adv
  • Used to indicate a context of urgency. 

  • Sometimes; occasionally. 

  • Used to address a switching side, or sharp change in attitude from before. (In this usage, now is usually emphasized). 

  • At the present time. 

  • Used to introduce a point, a qualification of what has previously been said, a remonstration or a rebuke. 

  • At the time reached within a narration. 

  • Differently from the immediate past; differently from a more remote past or a possible future; differently from all other times. 

intj
  • Indicates a signal to begin. 

noun
  • The state of not paying attention to the future or the past. 

  • The present time. 

  • A particular instant in time, as perceived at that instant. 

adj
  • Fashionable; popular; up to date; current. 

  • Present; current. 

till

conj
  • Until, until the time that. 

prep
  • Until; to, up to; as late as (a given time). 

  • To make it possible that. 

noun
  • A vetch; a tare. 

  • A cash register. 

  • glacial drift consisting of a mixture of clay, sand, pebbles and boulders 

  • manure or other material used to fertilize land 

  • A removable box within a cash register containing the money. 

  • The contents of a cash register, for example at the beginning or end of the day or of a cashier's shift. 

verb
  • To develop so as to improve or prepare for usage; to cultivate (said of knowledge, virtue, mind etc.). 

  • To cultivate soil. 

  • To work or cultivate or plough (soil); to prepare for growing vegetation and crops. 

How often have the words now and till occurred in a corpus of books? (source: Google Ngram Viewer )