Used in contexts of measuring or drawing straight lines.
El rasero que usó el carpintero era perfectamente recto, lo que facilitó la construcción del estante.
The ruler the carpenter used was perfectly straight, which facilitated the construction of the shelf.
El carpintero usó un rasero para asegurarse de que las tablas estaban perfectamente alineadas.
The carpenter used a ruler to ensure that the boards were perfectly aligned.