-O-

Object
SYNTAX: complement which is selected and directly governed by a lexical head.

Object control verb
SYNTAX: verb which selects both an NP and an infinitival clause as its complements and requires that the NP must °control the °PRO subject of the infinitival complement. EXAMPLE: A standard example is (i):

(i) John_j persuaded Susan_i [PRO_i/*j to leave]

Object language
°Meta language.

Oblique case
SYNTAX: non-canonical case which is assigned by a governing preposition. See °Of-insertion and °inherent case.
LIT. Chomsky (1981).

Oblique context
°Opaque context.

Obstruent
PHONOLOGY: a name referring to consonants (°stops and °fricatives) that are produced by narrowing or complete closure of the vocal tract; the air pressure is built up inside the cavity. Obstruents share the feature [-son].

Occlusive
°Plosive.

Of-insertion
SYNTAX: insertion of the preposition of in order to case-mark a NP object of a noun:

(i) [_NP the destruction of [_NP the city]]

The case assigned by the preposition of is generally referred to as oblique case.
LIT. Chomsky (1981, 1986a).

One-affix-one-rule hypothesis
MORPHOLOGY: a hypothesis which says that a word formation rule specifies a unique phonological operation which is performed on the base. It specifies a unique syntactic label and subcategorization frame, as well as a unique semantic reading. EXAMPLE: in English the suffix -er is used to form agent nouns (worker, player) as well as comparatives (quicker, happier). Given the differences in syntactic category and meaning, the one-affix-one-rule hypothesis entails that there are two -er affixation rules. This example seems rather trivial, but things become less trivial if one knows that -er is also used to form instrument nouns (hanger, glider) since the circumstances under which agent nouns and instrument nouns are formed are identical. The one-affix-one-rule hypothesis says that we have two rules here, but this claim does not explain the similarities between both rules of -er nominalization.
LIT. Scalise (1984).

One-place predicate
°Arity.

Opacity Condition
SYNTAX: condition which is in effect a reinterpretation of the °Specified Subject Condition as a condition on anaphors (including NP-traces). It is the precursor of °condition A of the °binding theory. The Opacity Condition states that

(i) An anaphor cannot be °free in the domain of the subject of beta, 
    beta minimal (beta = NP, S')

LIT. Chomsky (1980).

Opaque context
SEMANTICS: a context in which substitution of two expressions with the same °reference salva veritate (i.e. keeping the °truth value constant) is impossible. The verb hope in (ia) creates an opaque context. This can be seen by replacing the murderer of Smith with an expression which is assumed to have the same reference (in this case John's brother). The result in (ic) is a sentence which does not need to have the same truth value as (ia). One has only to imagine a situation in which John does not know that his beloved brother is the unknown murderer.

(i) a  John hopes that the murderer of Smith will be hanged
    b  The murderer of Smith is his (i.e. John's) brother
    c  John hopes that his brother will be hanged

Many different elements may create opaque contexts: words that express propositional attitudes (like know and believe, fear and hate), verbs like seek and want, temporal and modal expressions. Contexts of direct and indirect speech may also be opaque contexts. The pattern in (i) can be explained by making a distinction between °extension and °intension. The murderer of Smith and John's brother may have the same extension in a particular situation, but their intension, their meaning is different. A context which not opaque is called a transparent context.
LIT. Gamut (1991).

Open syllable
PHONOLOGY: a name for a °syllable without a consonant at the end: C₀ V or C₀ VV. EXAMPLE: all syllables in the English name A-me-ri-ca are open.

Operator
SYNTAX: element, such as a °quantifier (i) or a °wh-phrase (ii), which °A-bar binds a °variable (x) at °LF:

(i)  Mary loves someone
     LF: someone x, Mary loves x
(ii) Who does Mary love?
     LF: for which x, Mary loves x

LIT. Chomsky (1981).
SEMANTICS: a °logical constant (O) which is (usually) prefixed to a °formula phi in order to produce a new formula Ophi. The interpretation of this formula is a compositional function of the interpretation of phi. Negation is a truth-functional operator, which operates on the truth value of the proposition it is combined with. Modal operators (like necessarily) and tense operators (like it has been the case that) are not truth functional, because their interpretation does not solely depend on the truth value of the formula with which they combine, but also on the possible world or moment of time with respect to which the whole sentence is evaluated.
LIT. Gamut (1991).

Operator binding
SYNTAX: Binding by an °operator.
LIT. Chomsky (1981).

Oral
PHONOLOGY: oral sounds are produced without a lowered velum, so that the air can escape through the mouth, not through the nose (cf. °nasal).

Ordering hypothesis
°Level ordering Hypothesis.

Overgeneration
MORPHOLOGY: a property of (word formation) rules which entails that they are able to generate entities which are fully well-formed, but are not attested or used by the native speakers of a language. EXAMPLE: if the rule for -al affixation may derive attested forms such as arrival and refusal as well as unattested forms such as derival and describal, we say that the -al rule overgenerates.
LIT. Halle (1973), Spencer (1991).

Overlapping reference
SYNTAX: situation where two referring expressions are not °disjoint in reference, but not strictly °coreferential either. EXAMPLE: the ill-formed idiom *we lost my way requires we and my to be strictly co-referential (cf. I lost my way), but we and my only have an overlapping reference, hence the ill-formedness.
LIT. Chomsky (1981), Lasnik (1989).

Overt syntax
SYNTAX: (minimalist theory) syntax before Spell-out.
LIT. Chomsky (1992).