As others have indicated, these symbols are meant to represent the pronuncation of the word… but there's more, as the saying goes.
There are many different respelling systems, but this one is derived from a system created by Noah Webster. With some modifications, it remains in use by Merriam-Webster (see the MW Guide to Pronunciation), the American Heritage Dictionary (see the AHD Pronunciation Key), and other dictionaries published in the U.S.
This is the system which most Americans are taught in school, but it is only designed to represent American English, and is essentially unheard of in the rest of the world. I am somewhat surprised to see that it is the system Google employs internationally— for example, for Google.fr and Google.de as Googgle.co.id. No doubt this is because Google's information is sourced from an American dictionary.
The International Phonetic Alphabet (IPA) is elsewhere the standard, as it is designed to represent sounds from across all human languages, and this may be more familiar to you. The pronunciation of attractive would be rendered something like /ə ˈtræk tɪv/ in IPA.
Wikipedia has a U.S. dictionary transcription key which provides a "translation" of the notations from the Webster system to IPA. Also see What is the name for “pronunciation spelling”? at EL&U.