The Immigration and Nationality Act (INA) divides deportation in two separate categories:

Deportation for those who are seeking to enter the U.S. This category of deportation is called an “inadmissibility” proceeding under the section 212 of the Immigration and Nationality Act (“INA”); you may be seeking to “enter” even if you live in the U.S., but are merely returning from a temporary trip out of the U.S., e.g., a returning Legal Permanent Resident.
Deportation for those who are already in the U.S, i.e. those who have been “admitted or “inspected” – this category is now called a “removal” proceeding under section 237 of the INA.
There are significant differences not only between these two categories but also between each category’s basis for deportation. For example:

The “inadmissibility” conditions under section 212 (section which deals with people who have not yet entered the U.S.) do not contain any prohibitions against people who have committed gun crimes.
Conditions under section 237 (section dealing with people who are already residing in the U.S.) do contain prohibitions against people who have committed gun crimes and certain waivers available for persons in inadmissibility proceedings are not available to those in removability proceedings.
It is also critical to know that in inadmissibility proceedings the burden of proof in the case is on the non-citizen to demonstrate that he or she is entitled to remain in the United States. On the other hand, in removal proceedings, the burden of proof is on the government to demonstrate that the non-citizen committed a criminal offense, or violated the immigration law. This difference can have a substantial impact on how your case is decided by the judge and can mean the difference between being deported or not.

If you are being charged, you will receive a “Notice to Appear” which will state which section applies to you.

Both “inadmissibility” and “removal” proceedings are often simply referred to as “deportation” proceedings.