What is "electronic" in electronic codebook (ECB)? This is an honest question regarding terminology. I believe that I understand why one mode to use a block cipher is called a codebook. But I wonder why electronic as a work appears here? 

Is it fair to say this is just a fancy/stylish addition?
Should it relfect that often encyption is used with electrical devices?
Would ECB be impossible for a mechanic setup?
In a paper codebook, plaintext words (perhaps arranged alphabetically like in a dictionary) lead to a replacement word.

Cipher for Telegraphic Correspondence — a code book used by Union General Joseph Hooker’s code clerk. Source: wikipedia.

A block cipher implemented using electronic circuitry (as DES was initially) does the equivalent, with block instead of word, and new key instead of new book. That's thus an electronic codebook. The operating mode based solely only this feature is Electronic CodeBook.

It would be possible to implement a block cipher using non-electronic means, e.g. mechanic of even manual; and operate it in ECB mode. Fact is, this was not done on a large scale. Before DES, mechanical ciphers tended to operate on a letter-by-letter basis, not something wide comparable to a word.