The English language/vocabulary/verbal phrases

Also interesting are the collective nouns.

And this is something I already know, but I feel that everybody should know this: i.e. vs. e.g. Every time I see someone use one instead of the other, I feel like someone tossed a baton to trip me while I'm I was running.

I always make the mistake, it's very typical for non-English natives. I hope the tips for remembering the difference will be useful from now on 

 looking that one up in Urban Dictionary is NOT advised.

What context do you mean?
 

I have never heard of the compound word "gingerhead" though I have heard people say ginger headed or ginger topped and even ginger nut.

Ginger as a hair colour at first glance does not appear to make any sense because the natural redhead hair colour is orange and much closer in colour to copper, which is nothing like the colour of ginger root and the spice it is made into. Most dictionary sources give the ginger association with the red hair colour to the plant's flower ... 

Except I have a problem with that explanation... ginger plants rarely flower in Great Britain and very few Brits would have seen one in flower. (I have one growing on my windowsill and all I get is stalks and leaves). Also the red colour of the flowering bract is a vibrant red that bears no resemblance to hair colour, and we have many much more common red flowers and not one of them is used describe a hair colour - the closest we get is "strawberry blonde" for blonde hair with a reddish tint. The bright orange of carrots is sometimes used to describe redheads (carrot top), and they are certainly not red.

What is far more common in the UK are ginger cake and ginger biscuits ... and these do have a copper colour to them

So my contention is that the hair colour ginger refers to the colour of these baked products, possibly derived from the popular ginger biscuit called ginger nuts, where "nut" is also a slang term for the head:

Since "nut" (head) has a euphemistic pairing with "nuts" (testicles) then ginger nut is also used as a ribald double entendre since a man with ginger hair would also have ginger pubic hair on his nuts. This is considered to be hilarious in the school playground. 

I'm not sure. Ginger has known as a spice in the UK for a very long time, having been brought to England from India along the spice routes of the middle ages. Elisabeth I is said to have favoured gingerbread biscuits but that is probably a myth associated with her natural redhair. 

Ah treacle, what a rich nectar.  Without molasses we would not have rum or any of the dark stouts and porter beers of England, the oak brown rye breads, sticky-toffee pudding, treacle tart, pecan pie nor bitter black treacle toffee that is guaranteed to loosen the fillings from your teeth. 

Treacle and spice are just made for each other and no spice is better for that than the heat of ginger. This simpatico coupling of treacle and ginger also gives us the pleasure of rum and ginger, oft known by the cocktail name of Dark'n'Stormy, it delivers the kick of a Moscow Mule with the lingering warmth that only a smooth dark syrupy rum can produce.

Gingerbread is manna from heaven, the mix of treacle and ginger is a pairing that demands to be eaten, I frequently make this, sometimes by hand and sometimes in the bread-machine, and while it is a cake that improves with age, growing ever more sticky and treacle-like as it matures, it seldom lasts long enough in our house to reach that wondrous stage. Add to that pieces of stem ginger, crystallised ginger or caramelised pecans and the game is raised a notch higher, or use rolled oats to produce the Yorkshire treat of Parkin that makes the ubiquitous flap-jack pale by comparison.

Yum.