Noun domain has 5 senses
  1. sphere, domain, area, orbit, field, arena - a particular environment or walk of life; "his social sphere is limited"; "it was a closed area of employment"; "he's out of my orbit"
    --1 is a kind of environment
    --1 has particulars:
     distaff; front; kingdom, land, realm; lap; political arena, political sphere; preserve; province, responsibility
  2. domain, demesne, land - territory over which rule or control is exercised; "his domain extended into Europe"; "he made it the law of the land"
    --2 is a kind of region
    --2 is a part of country, state, land
    --2 has particulars:
     archduchy; barony; duchy, dukedom; earldom; emirate; empire; fiefdom; grand duchy; viscounty; khnate; kingdom, realm; principality, princedom; Kingdom of God; sheikdom, sheikhdom; suzerainty
  3. domain - the set of values of the independent variable for which a function is defined
    --3 is a kind of
  4. world, domain - people in general; especially a distinctive group of people with some shared interest; "the Western world"
    --4 is a kind of class, social class, socio-economic class
    --4 has particulars: academia, academe; Grub Street
  5. domain, region, realm - a knowledge domain that you are interested in or are communicating about; "it was a limited domain of discourse"; "here we enter the region of opinion"; "the realm of the occult"
    --5 is a kind of knowledge domain, knowledge base