centering vs concentration

centering

noun
  • The process of moving something to a centre, normally before some other process. 

  • A type of formwork which serves as a temporary structure during the construction of arches and bridges. 

concentration

noun
  • The act or process of removing the dress of ore and of reducing the valuable part to smaller compass, as by currents of air or water. 

  • The proportion of a substance in a whole. 

  • The act, process or product of reducing the volume of a liquid, as by evaporation. 

  • The direction of attention to a specific object. 

  • A field or course of study on which one focuses, especially as a student in a college or university. 

  • The amount of solute in a solution measured in suitable units (e.g., parts per million (ppm)) 

  • The matching game pelmanism. 

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