Spotlight is the system wide search functionality built into MacOS. It allows you to search for any document, folder or application on your system as well as giving you suggested web pages, videos online, dictionary definitions etc for your search terms. It's supper flexible and fast allowing you to easily find what you are looking for.
What else can Spotlight do?
What most people don't realise though is that Spotlight can also be used for a whole host of other things. Listed below are some of the more interesting.
How to Access Spotlight
You can access Spotlight by clicking on the magnifying glass in the menu bar top right of your display or by using the keyboard shortcut ? + Spacebar. The window can be repositioned anywhere on the display by clicking and dragging. You can also configure what Spotlight searches for by adding or removing a tick from the categories listed in System Preferences>Spotlight - Search Results tab.
App Launching
If you want to launch an installed app then simply start typing it's name. Apps are listed first in the 'Top Hits' section and pressing enter on the selected app will launch it.
Contact
Start typing the name of a contact and if they are in your address book then the relevant record is displayed. Hitting enter will open the Contacts app with the card required.
Calender Events
In the same way, type the name of an event that is in one of your calendars and the appropriate details will be displayed. Hitting enter will open the Calendar app and show you that event entry.
Conversions
Spotlight can be used to perform conversions for things like weights, measure and temperature. Simply type your amount in and it will give you a list of the common conversions for that item. For example type 30c and spotlight will give you the answer of 86?F/303.5 kelvins or type 2pounds and it will give you a list of relevant conversions to kilograms, ounces, grams, milligrams and short tons.
Calculations
Need a quick to use calculator - reach for spotlight. It will perform any calculation for you, just simply type your calculation into the search term and the answer will be displayed for you. Include brackets in order to get certain parts of the calculation evaluated first. ? + C will copy the result.
Currency Exchange Rate
Spotlight is able to check the current exchange rates and will give you a conversion. If you simply type a value such as £100 then it will give you a list of the most common currencies. Type £100 in YEN then it will display the amount for the exchange requested.
There are many more things that spotlight is capable of; search using keywords, use a more natural language for your search term (e.g. Events last month), get dictionary definitions, check the weather, look at sports scores etc. It's a very flexible and accessible part of MacOS and should become something you utilise in your every day Mac use.
Restricting Spotlight's Scope
Sometimes you may want to stop Spotlight from indexing a specific folder on your system - a Parrallels install or the cache to a photo app for instance or even a folder that contains sensitive information. It's possible to tell Spotlight to ignore these items (by default everything is indexed) simply visit System Preferences>Spotlight - Privacy tab. Click the plus button and navigate to the location of the item you wish to add to the exclusions list.