Scale is the relationship that the depicted feature on map has to its actual size in the real world. A map scale usually is given as a fraction or a ratio (e.g. 1/10,000 or 1:10,000). This means that 1 centimeter on the map is equal to 10,000 centimeters on the ground. The unit is interchangeable – 1 meter to 10,000 meters, 1 foot to 10,000 feet, and so on. The larger the second number is (10,000 in this case), the smaller the scale of the map. “The larger the number, the smaller the scale.” (Map Scales, USGS Earth Science Information Center)
As thoughtful map consumers and potential map makers, scale is important to understand as it affects feature representation.
To explore an example of small scale versus large scale representation see the GIS Lounge article, Understanding Map Scale, quoted above. Web maps you explore in this lesson and on your own will often provide higher scale maps with more detailed information when zoomed in, and lower scale maps with generalized features as you zoom out.