A rarer, more constructed form is polyptoton, the stylistic repetition of the same word or words derived from the same root:  As with cognate objects, these constructions are not redundant because the repeated words or derivatives cannot be removed without removing meaning or even destroying the sentence, though in most cases they could be replaced with non-related synonyms at the cost of style (e.g., compare "The only thing we have to fear is terror".) In many cases of semantic pleonasm, the status of a word as pleonastic depends on context. The relevant context can be as local as a neighboring word, or as global as the extent of a speaker's knowledge. In fact, many examples of redundant expressions are not inherently redundant, but can be redundant if used one way, and are not redundant if used another way. The "up" in "climb up" is not always redundant, as in the example "He climbed up and then fell down the mountain." Many other examples of pleonasm are redundant only if the speaker's knowledge is taken into account. For example, most English speakers would agree that "tuna fish" is redundant because tuna is a kind of fish. However, given the knowledge that "tuna" can also refer a kind of edible prickly pear, the "fish" in "tuna fish" can be seen as non-pleonastic, but rather a disambiguator between the fish and the prickly pear. Conversely, to English speakers who do not know Spanish, there is nothing redundant about "the La Brea tar pits" because the name "La Brea" is opaque: the speaker does not know that it is Spanish for "the tar". Similarly, even though scuba stands for "self-contained underwater breathing apparatus", a phrase like "the scuba gear" would probably not be considered pleonastic because "scuba" has been reanalyzed into English as a simple word, and not an acronym suggesting the pleonastic word sequence "apparatus gear". (Most do not even know that it is an acronym and do not spell it SCUBA or S.C.U.B.A. Similar examples are radar and laser.)