These words agree in meaning to increase in one or more dimensions. Extend , as here considered, means to increase a thing’s length, breadth or duration. An army may extend its supply lines; a bird extends its wings when soaring; and a tedious preacher may extend his sermon beyond his congregation’s span of attention.

Lengthen and draw out mean to extend a thing in length or in duration, but not in breadth. Draw out sometimes even implies a loss of breadth accompanying the increase in length; metal wires become both longer and thinner when they are draw out, elongate is used only to mean to lengthen spatially, not in time, and, like draw out , sometimes implies to extend in length at the expense of breadth, but in any case suggests disproportionately great length: one of the sculptor Giacometti’s mournful elongated figures.

Prolong and protract now usually refer to extended time, although prolong may also refer to space. Prolong implies an extension beyond natural or normal limits: to prolong the meeting until a quorum could be rounded up; to prolong a war by inept diplomacy and miscalculation of the enemy’s aims. Protract means to draw out or extend greatly in time; it is often used adjectivally: protracted negotiations covering four months of serious discussions.

Stretch , as here considered, means to extend a thing in length, breathe or in both dimensions: to stretch a sweater by pegging it out while wet. Stretch is now also used as an adjective applied to articles of clothing made of synthetic fibres that can be stretched to fit a variety of sizes: stretch socks. Widen means to increase only a thing’s breadth: to widen a highway by adding two lanes. Widen, like extend , may be used figuratively to apply to any broadening: to widen (or extend) one’s interests to include the study of nature.