【Surround】 , 【environ】 ,  【encircle】 ,  【circle】 ,  【encompass】 ,  【compass】 ,  【hem】 ,  【gird】 ,  【girdle】 ,  【ring】  can mean to close in or as if in a 【ring】 about something.

【Surround】 is a general term without specific connotations; it implies enclosure as if by a 【circle】 or a 【ring】 .

Often the term denotes not a literal enclosure but something which forms the circumstances, the environment, or the border of something.

【Environ】  also implies enclosure as if by a 【circle】 or a 【ring】 , but it often differs somewhat from  【surround】  in carrying a clearer implication of the permanent or continuing existence of what environs; thus, "a nation environed by foes" does not clearly imply as immediate danger as "an army surrounded by foes" does, but the former does suggest a persistent or ever-present danger in a way that the latter cannot. The difference is often slight but usually perceptible.

【Encircle】  is not quite the equal of  【surround】  though very like it in meaning and often interchangeable with it; it more definitely suggests an enclosing 【circle】 and therefore often is suited to a more concrete use; in this sense it is often equal to  【circle】 .

Also,  【encircle】  and  【circle】  may denote to proceed in a 【circle】 about something, a meaning unknown to  【surround】 .

【Encompass】 suggests something that closes in or shuts off a place or person; it often also suggests a motive (as protection or homage or hostility).

【Compass】 implies a being surrounded or encompassed usually by something that covers and protects or by something that weighs down upon and depresses.

【Hem】 , usually followed by an adverb and especially in , carries the strongest implication of confinement or of perfect enclosure of any of these words and often suggests difficulty or impossibility of escape.

【Gird】  and  【girdle】  both basically apply to an encircling of the waist with a belt or 【girdle】 .

【Gird】 is sometimes preferred when the meaning of to 【surround】 or 【encircle】 is expressed and the idea of a strong or insuperable barrier is implied.

【Girdle】 , on the other hand, tends to imply an encirclement suggestive of a belt or sash or constituting a zone and seldom connotes a tight or confining quality in what encircles.

【Ring】  carries a vivid picture of formation in a 【ring】 , but beyond this it has no particular implication. It is frequently chosen as a picturesque word in the senses of  【surround】  ,  【encircle】  , and  【hem】 in .