HOLLYWOOD (AP) _ You might be hearing a lot about it. So you might as well start learning how to pronounce it. ''Arachnophobia.''

That's ah-rak'-nah-foh'-bee-yah.

The summer movie season has offered more than the unsual dose of violent sequels and has yet to produce a runaway critical and commercial hit. Now, this new Disney film about nasty spiders is suddenly on the lips of many.

No one's saying ''Arachnophobia'' will be this year's ''Batman,'' which made $252 million in 1989. The eight-legged drama does have the potential, though, to emerge as one of the season's more unexpected successes.

In a campaign littered with high-priced, hardware-laden projects aimed at young male patrons, ''Arachnophobia'' and Paramount's ''Ghost,'' two modest, original works, appear to have a good chance of reaching a broader spectrum of the audience.

There are signs that a share of the audience is more interested in novel, non-sequel titles than the more heavily promoted and expensive cookie-cutter films.

On Wednesday, ''Arachnophobia,'' starring Jeff Daniels and John Goodman, opened to moderate but unspectacular business of about $1.2 million on more than 1,200 screens. ''Who Framed Roger Rabbit,'' by comparison, grossed $1.8 million in its first night on 999 screens two summers ago.

On Tuesday, Walt Disney Co. President Frank Wells predicted the thriller, the first release from Disney subsidiary Hollywood Pictures, would be one of the season's biggest hits. The head of a competing studio, speaking on condition that he not be identified, said ''Arachnophobia'' should open slowly and build forcefully on strong word of mouth.

CinemaScore, which tracks audience reactions to movies, said the film scored a B+ in surveys of 335 patrons Wednesday. That places it alongside ''Dick Tracy,'' but below ''Ghost,'' ''Days of Thunder'' and ''Die Hard 2,'' all of which earned an A rating.

Among the summer releases that have been savaged by reviewers are ''RoboCop 2,'' ''Betsy's Wedding,'' ''Fire Birds,'' ''The Adventures of Ford Fairlane,'' ''Cadillac Man,'' ''Quick Change'' and ''Ghost Dad.''

''Arachnophobia'' is about the invasion of a small California town by a deadly South American spider. In ''Ghost,'' a murdered man's spirit comes back to protect his lover and solve his own slaying.

On Monday and Tuesday nights, ''Ghost'' quietly made more money than Bruce Willis' noisy ''Die Hard 2,'' even though the latter film, made at an estimated cost of a staggering $62 million, was playing on more than twice as many screens.

''Jungle Book,'' the 1967 film re-released last Friday by Disney, enjoyed the best opening ever for an animated movie with $7.7 million last weekend, surpassing the $7.5 million collected by ''The Land Before Time'' in its debut weekend in 1988.

Independent distributor Miramax Films, seeking to exploit the barrage of films budgeted at $35 million and more, unveiled this week an inventive campaign for its August release ''The Unbelievable Truth.''

''This summer the seven major studios have spent over $700,000,000 on film negatives,'' the ad reads. ''In order to compete, Miramax is unleashing an unbelievable secret weapon. The Unbelievable Truth. Negative cost $200,000.''

While there's no ''Batman'' this summer, the season, now halfway finished, is hardly fizzling. In fact, it likely will be the second-best in Hollywood history, and it easily should exceed the 1988 holiday season returns of $1.7 billion.

''The business of some of these movies is incredible,'' said Tom Sherak, president of domestic distribution and marketing for 20th Century Fox. ''Shame on everybody for comparing it to last year.''

Said Barry London, president of Paramount's motion picture group: ''Some films, depending on who was in them and the knd of film they were, were coming in with unreasonably high expectations.''

The trade newspaper Daily Variety is predicting this summer's box-office take will be about $1.85 billion, as compared to the record-setting 1989 summer when moviegoers spent $2.04 billion.

''You can't expect records to be broken every week,'' said John Krier, president of Exhibitor Relations Co. Inc., which tracks box-office figures. ''But it's a good summer.''