A weapon is only a ranged weapon if it is listed as a simple/martial ranged weapon. Every such weapon also happens to have the Range property
Note that fifth edition defaults to Standard English when something is not defined in the rules; however, what a ranged weapon is, is defined. The section on "Weapon Properties" includes the following:
Every weapon is classified as either melee or ranged. A melee weapon is used to attack a target within 5 feet of you, whereas a ranged weapon is used to attack a target at a distance.
Range. A weapon that can be used to make a ranged attack has a range shown in parentheses after the ammunition or thrown property. The range lists two numbers. The first is the weapon's normal range in feet, and the second indicates the weapon's long range. When attacking a target beyond normal range, you have disadvantage on the attack roll. You can't attack a target beyond the weapon's long range.
If something requires a heavy weapon this doesn't mean the weapon needs to reach some arbitrary weight but that the weapon must have the Heavy property. Unfortunately this analogy doesn't hold for figuring out what ranged weapons are because it is not the Range property that matters but simply whether or not the weapon is classified as a ranged weapon.
We can look at the description of the wand and its statblock and see that no part of it states that the wand is a ranged weapon, nor is it listed on the weapons table as a ranged weapon.
Another way we could deduce this is from the fact that every single ranged weapon has the Range property and since the wand does not have the Range property, it can't be a ranged weapon (proof by contrapositive). But be careful, weapons with the Thrown property also have a range listed despite some of them not being ranged weapons; having the property is necessary but is not sufficient to show that something is a ranged weapons.
Ultimately, if something is a ranged weapon, it will appear in the ranged weapon section of the table, unless it is an exceptional case such as the Storm Boomerang, which is not on the weapon table and exists in a module for the game released well after the Player's Handbook and its weapon table. (Princes of the Apocalypse to be exact).
That said, a wand is not even a weapon
Wands are not listed in the Weapons Table and their statblock does not call them weapons so they are not weapons. For some more reading there is also the following Q/A: