Semi-colons

For separating complex items in a list-like sentence:
Sometimes a semi-colon may be used for indicating related concepts in a sentence identifying relevant additional information.
Look at the following example:

The following may be symptoms of pavor nocturnus: confusion when first awakening, especially for young children; disorientation, increasingly accompanied by a sense of panic; outbursts of anger often directed at their parents or partners (if they are adults) lasting until they become cognisant of their surroundings.

Notice in the sentence above, the list starts with a colon, the items in the list are separated by semi-colons, and there are also commas.

In the video associated with this lesson, Shaun identifies a set of conjunctive adverbs that have a relationship to semi-colons. Here is a longer list: accordingly, | furthermore | undoubtedly | moreover | still | besides | otherwise | thus | consequently | likewise | meanwhile | now .... but there are more than this.

For two closely related sentences
Semi-colons are used between two separate independent sentences that are closely related, effectively connecting them and creating a closer relationship than if you simply used and in between them (See Commas 1). Some joining words can be used in conjunction with a semi-colon: however, therefore, consequently...

The All Black has admitted having a drinking problem; this is the first step to recovery.

I knew the new policy would cause problems; unpopular austerity measures are now necessary to save the company.

I'm not superstitious; however, I never won a race wearing those socks.