Question: Omni Group's DICT client differs from the application known as Dictionary, developed by what company as part of macOS?

Context paragraphs:
OmniFocus: OmniFocus is a personal task manager by The Omni Group for macOS and iOS.  The declared goal of the program is to be able to capture thoughts and ideas into to do lists.  The program uses concepts and techniques described in the book Getting Things Done (commonly abbreviated as GTD) by David Allen.

Dictionary (software): Dictionary is an application developed by Apple Inc. as a part of macOS.  The application provides definitions and synonyms from various dictionaries, Wikipedia articles and a glossary of Apple-related terms.

OmniDictionary: OmniDictionary is a DICT client by The Omni Group.  Unlike Apple Computer's Dictionary, it retrieves definitions from the internet via the DICT protocol instead of a file on the hard drive.  Starting with the release of version 2.0.4 is now a universal binary.

The Omni Group: The Omni Group is a company that develops software for the macOS, iOS, and watchOS platforms.  The Omni Group was informally founded as a NEXTSTEP consulting company in 1989 by Wil Shipley, who immediately brought on Ken Case and Tim Wood.  The three incorporated together under the name Omni Development, Inc. in 1993, because the name "Omni Group" was taken by another Seattle firm.  Omni initially produced custom database software for the NEXTSTEP platform for clients such as the William Morris Agency and McCaw Cellular Communications (then Cingular Wireless; now AT&T Inc.).  During this period they also ported a number of games to NEXTSTEP, then later to Mac OS X (after Apple acquired NeXT in 1997).  Around 2000 the company decided to start focusing on their own consumer applications for the Mac, and as of 2004 the vast majority of their revenue came from their consumer products.  In 2003 Ken Case took over as the chief officer of Omni, and in March 2004 Wil Shipley left with another Omni employee, interface designer Mike Matas, to form Delicious Monster.  Matas later left for Apple.

Wil Shipley: William "Wil" Jon Shipley (born October 16, 1969) is a Macintosh software developer, best known for co-founding and heading The Omni Group in 1991, where he did consulting work and developed software for the NeXTSTEP operating system, Rhapsody and later Mac OS X.  His firm was one of a relative few to develop for Rhapsody, with the company's OmniWeb becoming the most popular browser for the platform.  While at Omni he won a record five Apple Design Awards for his company's products.  He went on to found a second notable software firm, Delicious Monster, with Mike Matas in 2004.  Delicious Library, the company's flagship product, won three more Apple Design Awards.

Cisco NAC Appliance: Cisco NAC Appliance, formerly Cisco Clean Access (CCA), is a network admission control (NAC) system developed by Cisco Systems designed to produce a secure and clean computer network environment.  Originally developed by Perfigo and marketed under the name of Perfigo SmartEnforcer, this network admission control device analyzes systems attempting to access the network and prevents vulnerable computers from joining the network.  The system usually installs an application known as the Clean Access Agent on computers that will be connected to the network.  This application, in conjunction with both a Clean Access server and a Clean Access Manager, has become common in many universities and corporate environments today.  It is capable of managing wired or wireless networks in an in-band or out-of-band configuration mode, and Virtual Private networks (VPN) in an in-band only configuration mode.

OmniWeb: OmniWeb is a proprietary Internet web browser developed and marketed by The Omni Group, currently developed exclusively for Apple's macOS operating system.  It is available as a free download.

Delicious Monster: Delicious Monster is a software company based in Seattle, Washington, that sells the shareware software program "Delicious Library".  Its founders are Wil Shipley, one of the three co-founders of The Omni Group, and Mike Matas, who worked as an interface designer at The Omni Group.  Matas left Delicious Monster in 2005 to work for Apple, but left the company in July 2009 to found Push Pop Press.

OmniGraffle: OmniGraffle is a diagramming and digital illustration application for macOS and iOS created by The Omni Group.

GNOME Dictionary: GNOME Dictionary, also called gnome-dictionary, is a DICT client written in C by Emmanuele Bassi and others.  It is part of the free software GNOME desktop suite.  It allows users to look up words in various dictionary sources.

Supporting paragraphs: OmniDictionary Dictionary (software)
Answer: Apple Inc.