Hazo Wani yanayin, gajimare ne, ana kiransa da (aerosol) a turance, Yanayin ya ƙunshi ɗigon ruwan na dindindin, kristal mai daskarewa, ko wasu barbashi da aka dakatar a cikin yanayin jikin duniya ko makamancin haka.[1] Ruwa ko wasu sunadarai daban -daban na iya tsara ɗigon ruwa da lu'ulu'u. A doron ƙasa, ana samun gajimare sakamakon ɗimbin iska lokacin da aka sanyaya shi zuwa raɓa, ko kuma lokacin da ya sami isasshen danshi (galibi a cikin yanayin tururin ruwa ) daga wani maƙwabcin kusa don ɗaga alamar raɓa ga yanayin zazzabi. Suna gani a Duniya ta homosphere, wanda ya hada da troposphere, stratosphere, kuma mesosphere.[2]
Nephology ne kimiyya na girgije, wanda aka Kanmu a cikin girgije kimiyyar lissafi reshen meteorology. Akwai hanyoyi guda biyu na ba da suna gajimare a cikin sahun su na sararin samaniya, Latin da na kowa.[3]
Ana iya samun asalin kalmar "girgije" a cikin tsoffin kalmomin Ingilishi clud ko clod, ma'ana tudu ko taro na dutse. A kusa da farkon karni na 13, an fara amfani da kalmar a matsayin kwatancen girgije na ruwan sama, saboda kamanceceniya a cikin bayyanar tsakanin babban dutsen da girgije mai tarin yawa. Da shigewar lokaci, amfani da kalmar kalma ta maye gurbin tsohon weolcan, wanda ya kasance kalma ta zahiri ga gajimare gaba ɗaya.[4]