Hashish (/həˈʃiːʃ/ ^ⓘ; from Arabic ḥašiš حشيش 'hay'), usually abbreviated as hash, is a compressed form of resin (trichomes) derived from the Cannabis flowers. As a psychoactive substance, it is consumed plain or mixed with tobacco. It has a long history of use in countries such as Afghanistan, India, Pakistan, Iran, Iraq, Lebanon, Morocco, Nepal and Egypt.

Hashish
1.5 grams (1⁄16 oz) hashish
Source plant(s)	Cannabis indica, Cannabis sativa, Cannabis ruderalis
Part(s) of plant	Trichome
Geographic origin	South Asia
Active ingredients	Tetrahydrocannabinol, cannabidiol, cannabinol, tetrahydrocannabivarin
Legal status	AU: S8 (Controlled drug) CA: Unscheduled DE: Anlage I (Authorized scientific use only) UK: Class B US: Schedule I UN: Narcotic Schedule I

Hashish consumption is also popular in Europe. In the United States, dried flowers or concentrates are more popular, and hash has seen a relative decrease in popularity following changes in laws that have indirectly allowed for the development and increased availability of cannabis extracts that are more potent than traditional hashish, although regional differences in product preferences exist. Like many recreational drugs, multiple synonyms and alternative names for hashish exist, and vary greatly depending on the country and native language.

Hashish is a cannabis concentrate product composed of compressed or purified preparations of stalked resin glands, called trichomes, from the plant. It is defined by the 1961 UN Single Convention on Narcotic Drugs (Schedule I and IV) as "the separated resin, whether crude or purified, obtained from the cannabis plant". The resin contains ingredients such as tetrahydrocannabinol (THC) and other cannabinoids—but often in higher concentrations than the unsifted or unprocessed cannabis flower. Purities of confiscated hashish in Europe (2011) range between 3% and 15%. Between 2000 and 2005, the percentage of hashish in cannabis end product seizures was at 18%. With the strength of unprocessed cannabis flowers having increased greatly in recent years—with flowers containing upwards of 25% THC by weight—the strength of hashish produced today and in the future is likely to be far more potent than in these older records.

The consistency and appearance of hashish is highly dependent on the process used and the amount of leftover plant material (e.g. chlorophyll). It is typically solid, though its consistency ranges from brittle to malleable. It is most commonly light or dark brown in color, though may appear transparent, yellow, black, or red. In recent years, the terpene hashishene was identified as possibly responsible for the characteristic smell and aroma of hashish, as compared to raw herbal cannabis.