The reaction,
${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{OH}+{\mathrm{CH}}_3\mathrm{COCl}\stackrel{\mathrm{pyridine}}{\to }{\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{OCOCH}}_3$ is called

When phenol is treated with acetic anhydride or acetal chloride in the presence of pyridine, then phenyl acetate is formed. The given reaction is an example of acetylation because the -OH group of phenol gets acetylated.