Which is the correct way to refer to the letter "Z" — "Zee" or "Zed"?

Solution 1:

The letter 'Z' is called:

• 'Zed' (/zɛd/) in British English and Commonwealth English (i.e., UK, Australia, Canada, India, South Africa, etc.)
  Note that this is also close to its name in several non-English languages: "zeta in Italian and in Spanish, zäta in Swedish, zet in Dutch, Polish, German, Romanian and Czech, zæt in Danish, zett in Norwegian, zède in French, and zê in Portuguese" (all names ultimately derived from the Greek letter zeta).

• 'Zee' (/ziː/) in American English and Newfoundland English (parts of Canada)

• 'Izzard' (/ˈɪzərd/) in Scottish English.

Now for which you should use in your case:

• The US almost exclusively uses 'Zee'. This is how it's taught to children in schools, and the name they're familiar with. If you use 'Zed' in your presentation, you call attention (a little) to your non-US-ness. Whether this is good or bad is for you to decide.

• On the other hand, if you use 'Zee' and the audience consists of a large number of non-Americans (which is possible at a university) or people who otherwise expect you to say 'Zed', some observant ones may notice that you chose to change your normal pronunciation. :-)

• From experience, it is my impression that most Americans are either aware of the alternative pronunciation 'Zed' or (more likely) can understand what you mean from context. So the probability of actual confusion is small, I feel, though the probability of distraction may be high enough for you to choose 'Zee'.

Solution 2:

Neither is any more 'correct' than the other. It's the equivalent of debating which of color/colour is the correct spelling. As you're giving a presentation, I would worry most about just ensuring that you're clear and consistent.

Given an American audience, I would assume the following:

• They will almost certainly use 'Zee' themselves. For the most part, the only Americans who use 'Zed' are those who've had significant exposure to a foreign presence or those that want to appear that they have.
• Assuming they're even slightly educated or culturally exposed, they will completely understand you when you say Component Zed, particularly if you're speaking with a British accent to 'prime them for it' so to speak. In fact, you could also go with something less standard like Component Zulu (from the NATO phonetic alphabet) as long as you did it in context and consistently.

Based on this, I would recommend going with whatever you're most comfortable with (presumably 'Zed'). My worry would be that if you try to adapt on the fly to 'Zee' that you'll slip up at some point and start interleaving them which would be much less clear than simply referring to them as 'Zed' throughout.

Good luck!