A Jigawatt is not a Gigawatt

A gigawatt is a real thing.  It is a billion watts, which is the metric unit for energy conversion.  According to the English rules of pronunciation, a G followed by an I is pronounced as a hard G, like “girl” or “gift” or “git to school and learn to talk American.”  Most people are familiar with the unit of data storage known as a “gigabyte”.

However, “gigawatt” is not the word used by Dr. Emmett Brown in Back to the Future.  In the movie, he states that the flux capacitor requires “1.21 jigawatts” to operate.  With a J, since a soft G wouldn’t be appropriate there.  When it means he is trapped in the past, Marty appropriately asks, “What the hell’s a jigawatt?”  There is no such thing as a jigawatt.  We have to assume it is a fictional quantity.  Presumably, it is a jillion watts.  Jillion is also a fictional word.

Edit: Oh, my.  I stand more or less corrected.  As suggested, here is the entry from Webster’s New Universal Unabridged Dictionary:

Online dictionaries, including webster.com, list both pronunciations.  Some list the hard G as the primary pronunciation, others list it as the secondary.  However, online dictionaries are somewhat suspect, as is any information found on the Internet.  I should probably get my hands on a dictionary of American English.  In any case, this may present somewhat of a professional quandary.  What would my colleagues think if I started talking about jigabytes and jigabits?