This is a typical example of a word that can have different meanings given its context. The Dutch language has many of these so called homonyms.

Three translations of "aankomen" are most common, I will illustrate each with an example:

1. to arrive [verb] [kwam aan, aangekomen]
– "De trein zal om 4 uur aankomen."
("The train will arrive at 4 o’clock.")

2. to gain weight
– "Te veel aankomen is slecht voor je gezondheid."
("Gaining too much weight is bad for your health." Note that it is "te veel" and not "teveel". This is one of the most common Dutch spelling errors, due to the fact that "teveel" is actually a word. "Teveel" is a noun and means "surplus".)

3. to touch
For example: you are in a museum and a sign says: "Niet aankomen!" ("Do not touch!")

Extra:
Read more on homonyms: http://en.wikipedia.org/wiki/Homonym

bon appetit! [expression]

This is a command form and it translates to "eat tastily" or "eat with taste".

Some of you might feel that we really need this wish in the Netherlands! 😉

An equivalent expression is: "Eet smakelijk!".

Related expression:
When you leave the table and others are still eating, you can say: "prettige voortzetting!". This means: "pleasant continuation".

Extra:
1. Read more on Dutch food and eating habits:
www.thehollandring.com/food.shtml
2. Go Dutch on some recipes!
www.godutch.com/windmill/recipes.asp?id=all&hist=2

goose [noun] [de gans, de ganzen]

Example:
1. Domme gans! : "Silly goose!".
2. Ganzenlever: "Goose liver".

"Gans" is also an adverb or adjective in Dutch, but not as common. If you use it as an adverb, it means "wholly". As an adjective, it means "whole".

Example:
"Het ganse land was gekleed in oranje."
("The whole country was dressed in orange".)

tap/faucet, crane [noun] [de kraan, de kranen]

Examples:
1. "Warm(/koud)waterkraan": warm/cold water tap/faucet.

2. "Kraanwater": tap water.

In Dutch bars and restaurants they will always try to sell you the overpriced mineral water in the small blue labeled bottles (often referred to by the popular brand name "Spa blauw"), but you can ask for "kraanwater". They might not give it to you though and yes, Dutch people too, think this is highly annoying.

To order mineral water with gas, ask for "Spa rood", which comes in a bottle with a red label.

3. "Kraanwagen": a truck with a crane.