clearance vs discharge

clearance

noun
  • The act of leaving the area of a stoppage. 

  • The first disposal in a chain that leaves the area of a stoppage, or a disposal that leaves the area of a stoppage itself. 

  • The act of clearing or something (such as a space) cleared. 

  • A permission for a vehicle to proceed, or for a person to travel. 

  • A permission to have access to sensitive or secret documents or other information. 

  • The act of kicking a ball away from the goal one is defending. 

  • The act of potting all the remaining balls on a table at one visit. 

  • Clear or net profit. 

  • The settlement of transactions involving securities or means of payment such as checks by means of a clearing house. 

  • A permission to use something, usually intellectual property, that is legally, but not otherwise, protected. 

  • The height or width of a tunnel, bridge or other passage, or the distance between a vehicle and the walls or roof of such passage; a gap, headroom. 

  • The distance between two moving objects, especially between parts of a machine 

  • A sale of merchandise, especially at significantly reduced prices, usually in order to make room for new merchandise or updated versions of the same merchandise. 

  • The removal of harmful substances from the blood; renal clearance. 

  • Removal of pieces from a rank, file or diagonal so that a bishop, rook or queen is free to move along it. 

discharge

noun
  • The act of expelling or letting go. 

  • The volume of water transported by a river in a certain amount of time, usually in units of m³/s (cubic meters per second). 

  • The process of flowing out. 

  • The act of firing a projectile, especially from a firearm. 

  • Pus or exudate (other than blood) from a wound or orifice, usually due to infection or pathology. 

  • The act of accomplishing (an obligation) or repaying a debt etc.; performance. 

  • The act of releasing an inpatient from hospital. 

  • The act of releasing an accumulated charge. 

  • The act of releasing a member of the armed forces from service. 

  • The process of unloading something. 

verb
  • To operate (any weapon that fires a projectile, such as a shotgun or sling). 

  • To send away (a creditor) satisfied by payment; to pay one's debt or obligation to. 

  • To relieve of an office or employment; to send away from service; to dismiss. 

  • To release (an accumulated charge). 

  • To release legally from confinement; to set at liberty. 

  • To let fly, as a missile; to shoot. 

  • To free of a debt, claim, obligation, responsibility, accusation, etc.; to absolve; to acquit; to forgive; to clear. 

  • To release (an auxiliary assumption) from the list of assumptions used in arguments, and return to the main argument. 

  • To unload a ship or another means of transport. 

  • To give forth; to emit or send out. 

  • To release (an inpatient) from hospital. 

  • To put forth, or remove, as a charge or burden; to take out, as that with which anything is loaded or filled. 

  • To set aside; to annul; to dismiss. 

  • To bleach out or to remove or efface, as by a chemical process. 

  • To release (a member of the armed forces) from service. 

  • To accomplish or complete, as an obligation. 

  • To expel or let go. 

  • To let fly; to give expression to; to utter. 

How often have the words clearance and discharge occurred in a corpus of books? (source: Google Ngram Viewer )