There was a time when, if you wanted to buy a complete set of some publication which came in its own slip-case, it was known as a “boxed set”. The OED records this from as early as 1895 (Chicago Tribune, 22 December: “The boxed set of three volumes”), and in the case of recorded music, from 1947 (New Yorker 22 March: “Columbia’s two-volume boxed set of Handel’s â€˜Messiahâ€™”). This usage has continued up to the present day (OED has “Though some of the films are available as singles, the boxed set contains added features on the bonus disc.” from the Montreal Gazette, 3 June 2006).
However, increasingly the form “box set” is used. I was surprised to find that the OED records this as early as 1969 (Appleton Post Crescent, 26 October: “Box set of 8â€“12 oz. Tumblers” – Appleton is in Wisconsin for those like me who were previously unaware of its geographical location).
I have always assumed that the shorter form came about because of phonetic simplification of the cluster /sts/, removing the /t/ from the middle, but now, in a single edition of a British newspaper I find three examples of similar phrases: terrace house, for which I have always said terraced house, and these: “[This company] offers ‘gigabit fibre’ broadband to select customers in London”; “online shoppers who buy through select websites”.
“Terrace house” appears in Jane Austen’s Sanditon and James Joyce’s Ulysses, so it has a very long pedigree, and in fact, the OED refers you to ‘terrace house’ if you first look up ‘terraced house’, which it can only date back to 1958 (Daily Express, 3 April: “Their tiny terraced home in the back streets of Horden, Durham”).
“Select” seems to me to have a different meaning than “selected”. A website, or a customer, is selected when it is chosen maybe at random, whereas a “select customer” or “select website” is one picked out for some special reason of excellence. The OED appears to agree with me. Are we witnessing a change in the language from adjectival -ed forms based on nouns to bare nouns, and also to the removal of the -ed from adjectives derived from verbs?