sub·di·vide /ˌsʌbdəˈvaɪd, ˈsʌbdəˌ/
  (v.)再分;細分;細別
  Sub·di·vide v. t. [imp. & p. p. Subdivided p. pr. & vb. n. Subdividing.]  To divide the parts of (anything) into more parts; to part into smaller divisions; to divide again, as what has already been divided.
     The progenies of Cham and Japhet swarmed into colonies, and those colonies were subdivided into many others.   --Dryden.
  Sub·di·vide, v. i. To be, or to become, subdivided.
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  subdivide
       v 1: form into subdivisions; "The cells subdivided"
       2: divide into smaller and smaller pieces; "This apartment
          cannot be subdivided any further!"