Isilinganiso
Isilinganiso siwukungakanisa ubungako bento noma isehlo, ukuze kusetshenziswe ukuqhathaniseni nezinye izinto noma izehlo. Ngamanye amazwi, isilinganiso siyinqubo yokunquma ubukhulu noma ubuncane bomgangatho obonwayo uma kuqhathaniswa nephatho eliyisiseko lomgangatho wohlobo olufanayo. Ubunjalo nokusetshenziswa kwesilinganiso kuncike komongo nomkhakha okukhulunywa ngawo. Kwezenzululwazi yemvelo nezobunjiniyela, izilinganiso azibhekiseli ezakhini ezicatshangwayo zezinto noma izehlo, okuhambisana neziqondiso zenhlangano ebhekele ízisindo nezilinganiso emhlabeni. Kodwa, kweminye imikhakha efana nezibalo kanye nezinzululwazi zomphakathi nokucondoza, izilinganiso zingaba namazinga amaningi, angahlanganisa lawo acatshangwayo, aqondile, angumgama kanye namanani okuqhathanisa.
Isilinganiso siwumgogodla wohwebo, inzululwazi, ubuchwepheshe nocwaningo lokungakanisa kwezoqeqeshwa eziningi. Ngokomlando, ziningi izinhlelo zokulunganisa ezazikhona zemikhakha ehlukahlukene yokuphila kwabantu ukuze zilekelele ekuqhathaniseni kuleyo mikhakha. Ngokuvamile lokhu kwakufezekiswa izivumelwano zasendaweni phakathi kwabahwebelanayo. Kusuka ngekhulu le-18, izintuthukiso zaqombolela ekuhkanganiseni, izindinganiso ezamukelwe kabanzi ngokuzihlanganisa zibe isimiso semivo somhlaba ( International System of Units (SI). Lesi simiso sinciphisa zonke izilinganiso zibe inhlanganiso yomchazazibalo yemivo yesibalo isikhonbisa. Inzululwazi yokulinganisa iphishekelwa emkhakheni womchazakulingana (metrology).
Isilinganiso sichasiswa njengomdludlungu wokuqhathanisa umngakonani ongaziwa ngomngakonani owaziwayo.