A “technical” is a type of improvised fighting vehicle, typically a civilian or military non-combat vehicle, modified to provide an offensive capability similar to a military gun truck.

It is usually an open-backed civilian pickup truck or four-wheel drive vehicle mounting a machine gun, light anti-aircraft gun, recoilless rifle, or other support weapon.

The term technical describing such a vehicle originated in Somalia in the early 1990s. Barred from bringing in private security, non-governmental organizations hired local gunmen to protect their personnel, using money defined as “technical assistance grants”. Hence the term.

Eventually the term broadened to include any vehicle carrying armed men. Technicals have also been referred to as battlewagons, gunwagons, or gunships by certain groups and commentators..

An alternative explanation is that the term was first used in Somalia in the 1980s, after engineers from Soviet arms manufacturer Tekniko mounted weapons on vehicles for the Somali National Movement during the Somaliland War of Independence

Among irregular armies, often centred around the perceived strength and charisma of warlords, the prestige power of technicals is strong.

Who says Charlie don’t surf!

A warlord’s power is measured by how many of these vehicles he has.”^[3] Technicals are not commonly used by well-funded armies that are able to procure purpose-built combat vehicles, because the soft-skinned civilian vehicles that technicals are based on do not offer very good protection to their crew and passengers.

Information for this post was gained from Military wiki.