focus vs sidetrack

focus

verb
  • To concentrate one’s attention. 

  • To adjust (a lens, an optical instrument) in order to position an image with respect to the focal plane. 

  • To transfer the input focus to (a visual element), so that it receives subsequent input. 

  • To direct attention, effort, or energy to a particular audience or task. 

  • To concentrate during a task. 

  • To cause (rays of light, etc) to converge at a single point. 

  • To aggregate figures of accounts. 

noun
  • The fact of the convergence of light on the photographic medium. 

  • A point of a conic at which rays reflected from a curve or surface converge. 

  • The most important word or phrase in a sentence or passage, or the one that imparts information. 

  • The quality of the convergence of light on the photographic medium. 

  • A point at which reflected or refracted rays of light converge. 

  • The exact point of where an earthquake occurs, in three dimensions (underneath the epicentre). 

  • The status of being the currently active element in a user interface, often indicated by a visual highlight. 

  • Concentration of attention. 

  • An object used in casting a magic spell. 

sidetrack

verb
  • To divert or distract (someone) from a main issue or course of action with an alternate or less relevant topic or activity; or, to use deliberate trickery or sly wordplay when talking to (a person) in order to avoid discussion of a subject. 

  • To deviate briefly from the topic at hand. 

  • To sideline; to push aside; to divert or distract from, reducing (something) to a secondary or subordinate position. 

  • To divert (a locomotive or train) on to a lesser used track in order to allow other trains to pass. 

noun
  • An alternate train of thought, issue, topic, or activity, that is a deviation or distraction from the topic at hand or central activity, and secondary or subordinate in importance or effectiveness. 

  • A second, relatively short length of track just to the side of a railroad track, joined to the main track by switches at one or both ends, used either for unloading freight, or to allow two trains on a same track to meet (opposite directions) or pass (same direction); a railroad siding. 

  • Any auxiliary railroad track, as differentiated from a siding, that runs adjacent to the main track. 

  • A smaller tunnel or well drilled as an auxiliary off a main tunnel or well. 

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