PIV may refer to:
Language Plena Ilustrita Vortaro de Esperanto, a dictionary of Esperanto Vaeakau-Taumako (ISO 639 language code), a Polynesian language
Science and technology Particle image velocimetry, an optical method of flow visualization Peak inverse voltage, in electronics Pentium 4 microprocessor, produced by Intel ("IV" is Roman numeral for "4") Personal Identity Verification, as specified by the US federal government standard FIPS 201 Positive input ventilation, a type of ventilation for buildings Post indicator valve, a shut-off valve for otherwise underground pipes, notably for fire sprinklers; see Glossary of firefighting equipment#P Pivaloyl protecting group (Piv), a protecting group in chemistry P = IV, the formula describing power in terms of current and voltage in electrical power
Medicine Parainfluenza virus, single-stranded RNA viruses belonging to the Paramyxoviridae family Peripheral intravenous catheter (PIVC), in medicine Posterior interventricular artery, an artery supplying the heart
Other uses Penis in vagina, a type of sexual intercourse PIV (gang), a Belize City street gang