The term "synonyms," in everyday parlance, denotes two or more words sharing the same or closely allied meaning.

In "Synonyms," the Choo San Goh opus, which was the chief novelty of last night's Washington Ballet program at Lisner Auditorium (the work has been out of the company repertory for several years), the signification is considerably more elusive. Indeed, poetic ambiguity is one of the ballet's main attractions, along with a haunting, almost indefinable emotional quality that has something to do with the idea of soul mates.

"Synonyms" was created in 1978, to the first three movements of Benjamin Britten's fittingly misty String Quartet No. 1. It's the most mysterious, in every sense, of Goh's ballets. Ostensibly, it's an abstract ballet, and an interestingly structured one, for two principal females and four couples.

But both the title and the choreography suggest areas, if not specific locales, of meaning. The paired leads (Lynn Cote and Julie Miles) dance side by side, back to back, sometimes in parallel, sometimes in opposition, sometimes reaching to or chasing one another, sometimes so closely aligned they seem like one being with four limbs. Are they alter egos--opposing sides of the same individual? Are they doppelga ngers, perhaps, or twins? Rivals, or lovers? The ballet, with its alternating distance and proximity, attractions and antagonisms, supports any or all of these readings; that's its core and fascination.

The choreography for the four supporting couples ramifies and embroiders each of these possibilities, as the dancers separate into male-female contigents or link up, now in sexy couplings, now in hostile confrontations.

The original cast featured two exceptionally tall, incisive women--Miles and Robin Conrad (the latter no longer with the troupe)--as the leads. Cote, who is short, has so mastered the crux and tone of the ballet, though, that the disparity in height never even entered awareness. Miles, too, was excellent, as was the ensemble, in what proved to be an altogether engrossing performance.

Goh's "Birds of Paradise," repeated from Wednesday's opening night program, also highlights two principal women, in this case both partnered by men (Brian Jameson and John Goding). Making role debuts as the leads last night were Bonnie Moore and Janet Shibata, who danced splendily. Moore was aptly flamboyant; Shibata needs to find a bit more aggressiveness and acuity. Opening the program was Balanchine's "Allegro Brillante"--it's a test of technical and stylistic mettle the company once again passed with high honors; Moore was at her most scintillating in the lead, with Stephen Baranovics as her deft partner.

Last night's program repeats this evening; the opening bill will be danced in Saturday's concluding matinee and evening performances.