Final answer:
The abbreviation for an ointment form of a drug is 'ung', referring to 'unguentum'. Other abbreviations like 'gtts', 'susp', and 'soln' denote drops, suspension, and solution, respectively.
Step-by-step explanation:
The abbreviation that indicates an ointment form of a given drug is "ung", which is short for unguentum, the Latin term for ointment. The other abbreviations you've mentioned refer to different forms of medication: "gtts" stands for drops (from the Latin 'guttae'), "susp" is an abbreviation for suspension, and "soln" stands for solution.