rialaigh, v.t. & i. Rule. 1. Govern, control. Tír a rialú, to rule a country. Teaghlach a rialú, to control a household. 2. Jur:Rialú (go), to rule (that). A rialú go bhfuil rud as ordú, to rule sth. out of order. 3. Regulate. Cíos a rialú, to control rent. Clog a rialú, to regulate a clock. 4. Gram: Govern. Rialaíonn sé an t-ainmfhocal sa ghinideach, it governs the noun in the genitive case. 5. Line. Páipéar a rialú, to rule paper.