You guessed right: "4:3 ploÈio" means "in wide". There's a Lithuanian diacritic pronounced "ch" which confuses. Yet the overall meaning remains unclear because 4:3 seems to represent rather both height and width (or area) than merely width. "4/3" is the accepted form to represent part of the entire width. In case the format is meant (e. g. of a TV screen) the word "pločio" would be inappropriate ("formato" should be used instead; sometimes "ekrano santykis [proportion] 4:3" (is used in Lithuanian texts)