horizontalhor·i·zon·tal /ˌhɒrəˈzɒntl◂ˌhɑrəˈzɑːntl◂/ adjectiveadjHUMAN RESOURCES1a horizontal organization has no or few levels of managementa horizontal organization with the emphasis on working as a team
2relating to the same level in an organizationHis change of responsibilities is a horizontal move rather than a promotion.