Grams per square metre, (unit for measuring the weight of paper)(initialism)
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Use "gsm" in a sentence
"Just purchase the other phones (a cheap one and a gsm international one) and you can swap your SIM Card from phone to phone, transfering your number very easily."
"A cdma-based iPhone is very possible with the release of the r-uim card (a removable id chip for cdma phones … kind of like a sim card for the gsm phone) in the American market."
"The soft-spoken hacker put the small FPGA firm in the spotlight at the ShmooCon security symposium in 2008 when he and fellow researcher Steve Muller revealed a tool for breaking the encryption that protects gsm cell phone signals, including those used by AT&T and T-Mobile."