▁organiz ational ▁unit ▁( OU ) ▁provides ▁a ▁way ▁of ▁class ifying ▁objects ▁located ▁in ▁directories , ▁or ▁names ▁in ▁a ▁digital ▁certificate ▁hierarchy , ▁typically ▁used ▁either ▁to ▁differenti ate ▁between ▁objects ▁with ▁the ▁same ▁name ▁( John ▁Do e ▁in ▁O U ▁" mark eting " ▁versus ▁John ▁Do e ▁in ▁O U ▁" customer ▁service "), ▁or ▁to ▁par cel ▁out ▁authority ▁to ▁create ▁and ▁manage ▁objects ▁( for ▁example : ▁to ▁give ▁rights ▁for ▁user - cre ation ▁to ▁local ▁techn icians ▁instead ▁of ▁having ▁to ▁manage ▁all ▁accounts ▁from ▁a ▁single ▁central ▁group ). ▁ ▁Organ iz ational ▁units ▁most ▁commonly ▁appear ▁in ▁X . 5 0 0 ▁directories , ▁X . 5 0 9 ▁certific ates , ▁Light weight ▁Directory ▁Access ▁Pro tocol ▁( LD AP ) ▁directories , ▁Active ▁Directory ▁( AD ), ▁and ▁Lot us ▁Notes ▁directories ▁and ▁certificate ▁trees , ▁but ▁they ▁may ▁feature ▁in ▁almost ▁any ▁modern ▁directory ▁or ▁digital ▁certificate ▁container ▁grouping ▁system . ▁ ▁In ▁most ▁systems , ▁organiz ational ▁units ▁appear ▁within ▁a ▁top - level ▁organization ▁grouping ▁or ▁organization ▁certificate , ▁called ▁a ▁domain . ▁In ▁many ▁systems ▁one ▁O U ▁can ▁also ▁exist ▁within ▁another ▁O U . ▁ ▁When ▁O Us ▁are ▁nested , ▁as ▁one ▁O U ▁contains ▁another ▁O U , ▁this ▁creates ▁a ▁relationship ▁where ▁the ▁contained ▁O U ▁is ▁called ▁the ▁child ▁and ▁the ▁container ▁is ▁called ▁the ▁parent . ▁ ▁Thus , ▁O Us ▁are ▁used ▁to ▁create ▁a ▁hierarchy ▁of ▁containers