Learn English – Why are setup windows called “wizard”

I can understand why the connection between these two senses of "dispose" seems so mysterious. The key to understanding it is: "to get rid of" is actually a secondary sense, even though today it is very common. The primary sense is "to put things into their proper places". The primary sense is now rare, but it still colors and explains the secondary senses.

Putting things into their proper place

When you dispose of garbage, you put it into its proper place: a garbage can, the city dump, or someplace like that. When you dispose of radioactive waste, you put it someplace very far away from people. However, throwing away garbage is only one of many ways that things can be "disposed of".

I marveled at the ability of a South China crime boss to dispose of these resources and organizational refinements with such precision. [Source]

Here, "dispose of" doesn't mean "get rid of" those resources, it means to put them to work in a coordinated manner—that is, to bring them to the proper places for performing some large, coordinated action.

In the Order Disposal Problem:

A manufacturer … may receive and dispose many production orders during a time period [but] he can dispose at most one order at any time due to resource constraints.

the word "dispose" means "to complete a job"—another way in which something can be put into its settled and proper place.

Being ready to act

Here is an example of saying that someone is disposed to act in a certain way:

Virtually all soldiers at all times have been strongly disposed to obey orders to go to war irrespective of whether the war has been just or unjust. [Source]

This calls upon another secondary sense of dispose: to put into a state of readiness to do some action—the action that one is disposed to or toward. The elements of one's mind, one's habits, one's abilities, one's resources, one's knowledge, one's surroundings, etc. are in a configuration that makes one especially ready to perform the action. This sense also occurs in sentences like this:

His generation and his origins dispose him to be a democrat. [Source]

Figuring out more senses of dispose

The word "dispose" gets used for many, widely varying meanings—more than I can list here, and indeed more than you'll find in dictionaries. Once you understand the primary meaning, it becomes a lot easier to understand how people are extending that meaning to fit different situations.

I think it helps to know the etymology, both for understanding the many senses of "dispose" and for many other words that contain the same two roots: dis- and pose. "Dis-" (in "dispose") is a Latin root meaning to break apart and spread out, as in disperse, disseminate, dissolve. "Pose" is a Latin root meaning to put something in a certain place or state, as in position, opposite, repose.

Knowing that, you might be able to figure out that a disposition can mean both an inclination toward doing something and the result of doing something—"where" things ultimately got put. The latter sense is rare, but an example is that in computers, a task is sometimes said to have a "disposition" of succeeded/failed/aborted. Another one is:

I can put five employees at your disposal.

This means that I can bring five employees to the appropriate place, where they will be ready to do as you command.

And finally, here's a stock phrase which is worth knowing, because it sheds a lot of light on the other senses: propose and dispose. Here's an example:

Men propose; women dispose. [Source]

This means that men offer possibilities to consider (propose), and women decide which proposals to carry out and which to reject (dispose—that is, sort out the proposals and bring some but not all to action).

Black Friday was either first used in November 1951 to describe factory workers taking sick days, or in 1966 in Philadelphia to describe the rush of people coming into the city for Army/Navy football games.

The term 'black' for a bad market day was already established by sometime in the late 19th century, and the US had a historic 'Black Monday' and 'Black Tuesday' in 1929 which have been recognized as the start of the Great Depression, where the Dow Jones lost almost 25% of it's value over the course of both days. There was likely *a* Black Friday before then, but the term as used today seems to have originated in one of the following places:

1. According to the an article in The Atlantic, the first modern(ish) use of the term was in an article of Factory Management and Maintenance in 1951, where it was associated with the widespread 'sickness' that seemed to befall factory workers the day after Thanksgiving. Already known as a big shopping day, it was recommended that factory management offer the day as an extra holiday as a 'bargaining chip' with unions, since the day was already one of relatively little production. The author used the term again in a February 1952 issue when mentioning that one company did indeed add 'Black Friday' to their list of paid holidays.

2. Other Sources say Black Friday became widespread in Philadelphia as a term by police officers describing the awful traffic, crowds, and behavior of tens of thousands of people showing up for the annual Army-Navy game in the '60s and shopping while they were there and off work. It appears to have been in normal use by the police department as early as 1961 (along with "Black Saturday"). The term became used widely for the day after Thanksgiving, to the dismay of retailers who disliked the negative connotations. A couple of decades later, after some not-so-successful campaigning to change it to 'Big Friday', retailers finally accepted the name, and changed the meaning of 'black' to be the day that they went from 'in the red' to 'in the black', because of the revenue earned that particular day.

Clearly, the name did begin with plenty of negative intent. It has since been co-opted by clever marketers and, since the origin was forgotten, has lost the negative slant.

Snopes has a great rundown that lists the key quotes from several sources, if you're interested.