Strain engineering, which employs biaxial misfit strain to deform the crystal structure, is a powerful tool to tune the physical behavior of epitaxial thin films. Here we show that a 10-nm-thick BiFeO${}_{3}$ film is uniaxially strained by (110)-oriented LaAlO${}_{3}$ substrate, which exhibits a monoclinic lattice with a giant $c$/$a$ \ensuremath{\sim} 1.24 and a unique stripe ferroelectric domain configuration, as revealed by high resolution synchrotron x-ray diffraction and piezoelectric force microscopy. A strain-phase diagram for BiFeO${}_{3}$ under uniaxial strain condition is predicted by first-principles calculations, suggesting that monoclinic $Pm$ phase with a large polarization of \ensuremath{\sim}130 \ensuremath{\mu}C/cm${}^{2}$ is the lowest-in-energy phase when strained by (110)-oriented LaAlO${}_{3}$ substrate. Our results provide a potential route to tune physical behavior of epitaxial ferroelectric thin films by uniaxial strain in (110) orientation, instead of widely investigated biaxial strain in (001) orientation.