Hopefully this will be an easy question to answer.
Under LatLngBounds ( https://developers.google.com/maps/documentation/javascript/reference#LatLngBounds ), the extend() function takes an argument, point:LatLng. Now, under Map ( https://developers.google.com/maps/documentation/javascript/reference#Map ), the panTo() function takes an argument, latlng:LatLng. What’s the difference between the two? And what does the part before the colon signify? I’ve seen others too, like other:LatLng.
In this case “latlng”, “point” or “other” is only a brief description of the parameter. The important thing is the token after the colon: It identifies the type of the parameter, in this case the parameter must be a object of the LatLng class.